Luminous Landscape Forum
Equipment & Techniques => Medium Format / Film / Digital Backs – and Large Sensor Photography => Topic started by: David Grover / Capture One on June 28, 2010, 04:04:04 pm
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I have started this thread as I wish to point out Mark's innacurate description of Leica's Autofocus system and also of ours.
Ill start with this quote...
An important thing that few photographers are aware of is that autofocus systems are not continuous; they work in zones. The Leica S2 has many more zones of focus from close up to infinity versus the competition. In other words, the S2 can focus more accurately at a specific distance.
This is absolutely not the case with Leica, Hasselblad, Canon or Nikon for that matter.
With a Phase Detection Auto Focus system we can measure any distance from near to infinity. There is a tolerance on the last measured focus error but this has still nothing to do with zones.
The only 'zoned' cameras were small compact cameras which used a different system to measure the approximate distance and then set the lens to one of a certain number of zones. Either a couple of zones or a few more.
Digital Compact cameras and I would guess cameras such as the Canon 5DMKII (in Live View mode) use contrast detection to determine focus. NOT zones!
If Mark had intended to mean Leica's last measured value was a higher tolerance than Hasselblad, Nikon and Canon then I would assume Mark would know our tolerance, Nikon / Canon's tolerance and finally Leica's tolerance. Please Mark, tell me your sources for these values - I have never seen these published anywhere?. I have not be asked by you for any information on the Hasselblad Auto Focus system.
Next....
Suppose I want to focus on a tree at about 200-300 feet. Using autofocus with a Medium Format camera, the system often goes into the infinity focusing zone. But, the tree is not at infinity. Add to this a high resolution MF back like a P65+, and the tree is guaranteed to look out of focus. Finally, focus shift could make matters worse if it goes the wrong way.
To be absolutely clear, this is not the way the Phase One 645DF works, or the Hasselblad H System.
Furthermore...
Most lenses suffer from focus shift as you change the aperture. This is a problem, since autofocus systems focus with the lens wide open. Hasselblad makes a correction (in the H4 series) with a software model. The camera figures out the lens, the focusing distance and aperture, and just before the exposure it applies an algorithm that re-focuses the lens. The problem is that the algorithm is based on one "ideal sample" lens. Unfortunately, each real lens differs somewhat from the “model lens”, so the system is not totally accurate. The PhaseOne lenses in my experience seem to have less focus shift. As far as I know, PhaseOne does not make any corrections to compensate for focus shift; PhaseOne users simply have to live with it.
We have been making this correction since the H1 was produced. Again, please check your sources, or actually request the information.
How do you know by how far the model lens deviates from a produced lens? Again this is not published information and for what it is worth the model lens is actually very close to the produced lens, close enough for the focus correction to work and to be of value.
Have you made specific focus shift tests on the Phase One and Hasselblad lenses? It would not be possible to test the Hasselblad lenses anyway as the focus correction cannot be switched off. So please tell me how you measured this compared to Phase One?
In conclusion, as usual a review on Luminous Landscape which mentions Hasselblad contains inaccurate information. I am more than happy to answer questions, supply technical data or even proofread articles for technical aspects. You only have to ask.
Best Regards,
David
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who really gives anything on Mark D.'s pointless essays (only containing claims based on half knowledge)...?
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Re. AF, the question is not only what can the camera measure, it is also what can the lens be set to by the camera's AF. In other words the design of the actuator on each lens comes into play.
I do think that Mark's review is a paper which the referees would like revised ....when I was organizing conferences, we would simply ask an author to take the referres's views into account, and the paper would usually get improved.
Edmund
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I can't speak to the accuracy of the writer's technical reasons WHY he feels that the autofocus on the Leica S2 is faster and more accurate than other camera systems he has owned or currently owns, but the point is that he still observed that the AF on the S2 IS faster and more accurate.
David
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... it appears that Lula sometimes is quite easy to understand nowadays:
first: one has just to bear in mind that "all is subjective", including autofocus mechanisms and dynamic range ...
and remember a few rules of thumb so that one can find one's way around here more easily:
Phase One > Hasselblad (the color is so awful)
Leica > Japanase 35mm (eaten alive)
Alpa > other technical cameras (sharper, better)
and not to forget: dont believe Puts, he should stick to his leica glass observations ...
but, all is subjective ...
And if you agree you can join and participate in a unique workshop where Phase One sponsors camera gear,
where you can try out some Alpas and Leicas ...
but don't listen to me, I think I'm being subjective
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I can't speak to the accuracy of the writer's technical reasons WHY he feels that the autofocus on the Leica S2 is faster and more accurate than other camera systems he has owned or currently owns, but the point is that he still observed that the AF on the S2 IS faster and more accurate.
David
My feeling of said speed is glacial, as *my* emotions seem to have bonded with my Nikon. Oh, and by the way, so far I've only met one MF camera which could focus almost decently and it's a plastic fantastic Hasslemebad. They have this model which does some vodoo and somehow changes focus as you wave it around. I even once tried using a camera called flexoreil or something, but I never got it to focus, and then suddenly !woosh! it was not for sale, I guess Leaves drop when autumn comes. Another camera I've used , the Mummykam, kind of wakes up focuses a bit and goes to sleep again and does so over and over - I think I can hear it snore, cough, stutter, snore. And then there is the Nikon! It says Yes! and it's sharp.
My opinion of this whole fiasco is that editorial discretion should have prevailed, someone should have told Mark to polish his piece *before* it went out, as he's a very smart guy he would have done so and controversy ,broken eggshells and ruined suits would have been avoided. However, a rewrite now might still make sense. And A nice brick wall photograph with brands P65, M9, S2, D3x and 5D2 would make my day. Please stick the $100 50mm/1.8 on the Nikon and Canon for the test.
Edmund
Edmund
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The article is in fact in error on the matter of autofocus.
I accept responsibility for not catching it. I prepared it for publication but did not read it carefully because I was in transit yesterday.
I have contacted Mark to see how he wants to handle editing the piece.
I apologize for the error.
Michael
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...that said, Mark's 'misstatement' correlates precisely with my real-world experience of the systems in question.
And yes, it is all subjective. Anyone who claims to be able to reduce anything of true significance in photography to fixed mathematical certainty is either a liar or a dullard, or both. So much is dependent upon the user's abilities and methods that any claims to 'universal' measures are essentially meaningless. To be honest, that's what makes it interesting. There's room for them all: the fanboys, the measurebators and the real photographers who take the time to share their subjective experiences.
- N.
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On top of that I have never seen a mf camera with more CA than the Leica. It's as bad as the canon when using one of their cheaper lenses. And if you are going to review something, review it. Mention the tethering is 3 hours and 9 minutes between images until you hit the buffer, then 6 hours each. Sorry kids the S2 had soooo much potential. I know of not one pro who makes his money shooting(not counting trust fund kids or seal) that has purchased one.
And he really used those pictures to test it????
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On top of that I have never seen a mf camera with more CA than the Leica. It's as bad as the canon when using one of their cheaper lenses. And if you are going to review something, review it. Mention the tethering is 3 hours and 9 minutes between images until you hit the buffer, then 6 hours each. Sorry kids the S2 had soooo much potential. I know of not one pro who makes his money shooting(not counting trust fund kids or seal) that has purchased one.
And he really used those pictures to test it????
I'm with Rogan. I shot a few frames with a production S2 in late March and I was alarmed at the CA. We're talking CA on the highlight on a black wristwatch placed in the middle of a frame shot in open shade - somewhere I've never seen CA before - and there wasn't any in the frame from the GF1 we were shooting with as well. The AF was fast and incredibly accurate, however...
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Question: How can you have accurate AF when the moment you recompose you've just thrown off the plane of focus from the point it was focused on? Incredibly accurate AF in all light and all lenses is what my 5D has. But like these systems it's only the center point. Moment you recompose, the plane of focus is shifted and you are relying on DOF to hold the focus for you. If there was ever anything that digital allowed us to see it was how false the perception of DOF is, the plane of focus is sharp, everything else is just less unsharp at any fstop until you hit diffraction and it evens out a bit.
I've never even seen the new 'blad and my 1Ds mkIII after 3 trips to canon still won't focus accurately with the off center points, I've no horse in this race. I do know however that focus is only ever going to be as accurate as the amount of recompose you are forced to do, especially the more megapixels you have to show focus differences.
A single point AF camera can only ever be described as 'incredibly accurate' if you always frame with the subject in the middle or stop down to the point that the accuracy is moot anyway.
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I can't speak to the accuracy of the writer's technical reasons WHY he feels that the autofocus on the Leica S2 is faster and more accurate than other camera systems he has owned or currently owns, but the point is that he still observed that the AF on the S2 IS faster and more accurate.
David
If that is mark's conclusion then of course I am not qualified to argue against it.
What I am more interested in is the accurate portrayal of AF systems in general and the misinformation regarding Hasselblad.
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The article is in fact in error on the matter of autofocus.
I accept responsibility for not catching it. I prepared it for publication but did not read it carefully because I was in transit yesterday.
I have contacted Mark to see how he wants to handle editing the piece.
I apologize for the error.
Michael
Thanks Michael. If Mark needs the correct information on Hasselblad he can always ask.
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Question: How can you have accurate AF when the moment you recompose you've just thrown off the plane of focus from the point it was focused on? Incredibly accurate AF in all light and all lenses is what my 5D has. But like these systems it's only the center point. Moment you recompose, the plane of focus is shifted and you are relying on DOF to hold the focus for you. If there was ever anything that digital allowed us to see it was how false the perception of DOF is, the plane of focus is sharp, everything else is just less unsharp at any fstop until you hit diffraction and it evens out a bit.
I've never even seen the new 'blad and my 1Ds mkIII after 3 trips to canon still won't focus accurately with the off center points, I've no horse in this race. I do know however that focus is only ever going to be as accurate as the amount of recompose you are forced to do, especially the more megapixels you have to show focus differences.
A single point AF camera can only ever be described as 'incredibly accurate' if you always frame with the subject in the middle or stop down to the point that the accuracy is moot anyway.
Excellent post.
Placing AF sensors out wide on an MF camera to a useful position would make them pretty hopeless, especially with shallow DOF.
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Hi,
Just because Mark was mistaken about zones in autofocusing it is quite possible that S2 autofocusing is simply better. It seems that Hasselblad has spent a lot of effort, behind the scenes, on improving real world AF-performance. They may deserve some credit.
Best regards
Erik
The article is in fact in error on the matter of autofocus.
I accept responsibility for not catching it. I prepared it for publication but did not read it carefully because I was in transit yesterday.
I have contacted Mark to see how he wants to handle editing the piece.
I apologize for the error.
Michael
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Hi,
Photography, technically seen, is applied physics, with some mathematics blended in. So scientific approach does apply to photography.
The art of photography has a lot to do with perception less with "science", but science is still there.
Best regards
Erik
...that said, Mark's 'misstatement' correlates precisely with my real-world experience of the systems in question.
And yes, it is all subjective. Anyone who claims to be able to reduce anything of true significance in photography to fixed mathematical certainty is either a liar or a dullard, or both. So much is dependent upon the user's abilities and methods that any claims to 'universal' measures are essentially meaningless. To be honest, that's what makes it interesting. There's room for them all: the fanboys, the measurebators and the real photographers who take the time to share their subjective experiences.
- N.
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Question: How can you have accurate AF when the moment you recompose you've just thrown off the plane of focus from the point it was focused on? Incredibly accurate AF in all light and all lenses is what my 5D has. But like these systems it's only the center point. Moment you recompose, the plane of focus is shifted and you are relying on DOF to hold the focus for you. If there was ever anything that digital allowed us to see it was how false the perception of DOF is, the plane of focus is sharp, everything else is just less unsharp at any fstop until you hit diffraction and it evens out a bit.
I've never even seen the new 'blad and my 1Ds mkIII after 3 trips to canon still won't focus accurately with the off center points, I've no horse in this race. I do know however that focus is only ever going to be as accurate as the amount of recompose you are forced to do, especially the more megapixels you have to show focus differences.
A single point AF camera can only ever be described as 'incredibly accurate' if you always frame with the subject in the middle or stop down to the point that the accuracy is moot anyway.
Exactly!
Thanks for this precision Ben.
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Some thoughts however: it is curious how in those days photographers have focussing problems with MF and have to relay on DSLR ultra high tech to get things in focus...
It is like those new models who can not handle a 2K HMI and start to cry...
I wonder what would think Avedon of all that in his tumb.
But those where "real men" with the correct proportion of testosterons to handle any kind of situation and therefore knew how to focus properlly with unperfect gear, didn't they?
Do you have focus issues and need a dslr to fix them?
mmm...wired times really, wired times.
Ps precisions: my use of "real men" has nothing sexist but an image, as I've also noticed that women's Lu-La forum never complain about gear specs, or editorial errors, or
have focusing issues with their devices. They take pictures and generally pretty well. Who wears the trousers? But I knew that we still have a lot to learn from the ladies.
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I had a very nice demo at a Capture Integration event where I shot the S-2 for an hour or so, with a model and also landscape/cityscape scenes. A Phase One DF was also present and I used it, more than I expected.
There was a lot to love about the Leica (weather sealing, quality, handling, simplicity in shooting--regarding all of which Mark was dead on), but we need to get real.
The Leica is not faster or more accurate at focus than the Phase One, period. They are very similar in focus speed. From my demo, I would say that you would never get a shot with the Leica that you would miss with the Phase One due to either speed or accuracy issues. Both focus very well and very quickly in dim light. I was surprised at this because Leica was claiming that their focus was significantly and substantially better. It is better than the older Mamiya bodies, and better than my Contax 645 (in speed but not in accuracy), but not so as against the newest-generation Phase.
This does not even account for what happens when you recompose, as has been thoroughly covered in other posts. I can't comment on Hassy because one was not there for my use. However, I believe that, in theory, their method for compensating for re-composition might actually be the best focus system yet for a format limited to one-center-point focusing systems.
That being said, I do not see where focus-and-recompose has ever lead me, with any system, to have chronically unsharp or unacceptable pictures. This is true even with 35mm systems using 85mm 1.4 lenses wide open. Of course, no comparison at all between Canikon AF and any medium format system which are still completely primitive by comparison.
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Some thoughts however: it is curious how in those days photographers have focussing problems with MF and have to relay on DSLR ultra high tech to get things in focus...
It is like those new models who can not handle a 2K HMI and start to cry...
I wonder what would think Avedon of all that in his tumb.
But those where "real men" with the correct proportion of testosterons to handle any kind of situation and therefore knew how to focus properlly with unperfect gear, didn't they?
Do you have focus issues and need a dslr to fix them?
mmm...wired times really, wired times.
[political correctness snipped]
Here (http://www.luminous-landscape.com/tutorials/Digital%20Focusing.shtml)'s why focusing is a whole different ballgame these days. Nothing to do with testosterone or lack of focusing skills in modern photographers.
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I had a very nice demo at a Capture Integration event where I shot the S-2 for an hour or so, with a model and also landscape/cityscape scenes. A Phase One DF was also present and I used it, more than I expected.
There was a lot to love about the Leica (weather sealing, quality, handling, simplicity in shooting--regarding all of which Mark was dead on), but we need to get real.
The Leica is not faster or more accurate at focus than the Phase One, period. They are very similar in focus speed. From my demo, I would say that you would never get a shot with the Leica that you would miss with the Phase One due to either speed or accuracy issues. Both focus very well and very quickly in dim light. I was surprised at this because Leica was claiming that their focus was significantly and substantially better. It is better than the older Mamiya bodies, and better than my Contax 645 (in speed but not in accuracy), but not so as against the newest-generation Phase.
This does not even account for what happens when you recompose, as has been thoroughly covered in other posts. I can't comment on Hassy because one was not there for my use. However, I believe that, in theory, their method for compensating for re-composition might actually be the best focus system yet for a format limited to one-center-point focusing systems.
That being said, I do not see where focus-and-recompose has ever lead me, with any system, to have chronically unsharp or unacceptable pictures. This is true even with 35mm systems using 85mm 1.4 lenses wide open. Of course, no comparison at all between Canikon AF and any medium format system which are still completely primitive by comparison.
Yes,
But the reality with those 35mm AF lenses is that the focus ring is so bad that they must be accurate with their AF system, and they are.
Then when one uses a proper manual focus prime, the precision of the mechanism allow the couple brain+hand to be extremely precise, and with training the natural correction when recomposing is done with a very high level of accuracy.
All you need are lenses that are built such a way that become if I might say, part of the body.
Then, the precision is IMO superior to any automatised system in most situations, and speed and accuracy can be very high. If one experiments another reality is for lack of practise in manual focusing.
A 6th sense as to be trained, but with the right lenses, not with AF lenses.
Also, it is true that with the digital resolutions we have today, focusing (and focusing fast) has more importance than in film age,
but I think that all these focusing issues are indeed exacerbated in a world where we are used to get everything pre-coocked. No surprise.
I still like to go to the market and cook my meal by myself. (don't need mum for that)
IMO.
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I had a very nice demo at a Capture Integration event where I shot the S-2 for an hour or so, with a model and also landscape/cityscape scenes. A Phase One DF was also present and I used it, more than I expected.
There was a lot to love about the Leica (weather sealing, quality, handling, simplicity in shooting--regarding all of which Mark was dead on), but we need to get real.
The Leica is not faster or more accurate at focus than the Phase One, period. They are very similar in focus speed. From my demo, I would say that you would never get a shot with the Leica that you would miss with the Phase One due to either speed or accuracy issues. Both focus very well and very quickly in dim light. I was surprised at this because Leica was claiming that their focus was significantly and substantially better. It is better than the older Mamiya bodies, and better than my Contax 645 (in speed but not in accuracy), but not so as against the newest-generation Phase.
This does not even account for what happens when you recompose, as has been thoroughly covered in other posts. I can't comment on Hassy because one was not there for my use. However, I believe that, in theory, their method for compensating for re-composition might actually be the best focus system yet for a format limited to one-center-point focusing systems.
That being said, I do not see where focus-and-recompose has ever lead me, with any system, to have chronically unsharp or unacceptable pictures. This is true even with 35mm systems using 85mm 1.4 lenses wide open. Of course, no comparison at all between Canikon AF and any medium format system which are still completely primitive by comparison.
Guy,
If I recall, you wrote about this experience on the GetDPI forum back in December 2009. If you attended that CI event in early December down here in Miami, you used the same physical camera I had to test with for two weeks prior. This camera had pre-release firmware and Leica has since issued two major firmware updates, both of which improved AF performance (speed and accuracy). In fact the latest 1.0.0.16 firmware has noticeably improved on already good speed. Keep in mind that Mark Dubovoy wrote his review based on this latest firmware. I'd suggest trying out the S2 again in its current state to see the difference for yourself. If you are in Miami, I'd be happy to demo it for you.
David
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Guy,
If I recall, you wrote about this experience on the GetDPI forum back in December 2009. If you attended that CI event in early December down here in Miami, you used the same physical camera I had to test with for two weeks prior. This camera had pre-release firmware and Leica has since issued two major firmware updates, both of which improved AF performance (speed and accuracy). In fact the latest 1.0.0.16 firmware has noticeably improved on already good speed. Keep in mind that Mark Dubovoy wrote his review based on this latest firmware. I'd suggest trying out the S2 again in its current state to see the difference for yourself. If you are in Miami, I'd be happy to demo it for you.
David
David,
This camera needs more happy shooters, rather than forum posts. In the end, the only thing which really advertises a camera is people **pro or not pro*** who say"I use this, it works for me".
A good example of this phenomenon is the 5D2, which is far from perfect as a movie cam, but which has established its reputation as a useful and profitable tool by finding a large untapped target audience.. The M8/M9 also have a crowd of people who like the rangefinder experience.
If you can find enough people like Mark or Erwin who enjoy the S2 experience, then the camera will fly. Find users who can benefit - but don't get into a fight with the others. I for one will value Guy's opinion of any camera at least as high as Mark's, because Guy has used a viewfinder to put his kids through college.
Edmund
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If I recall, you wrote about this experience on the GetDPI forum back in December 2009. If you attended that CI event in early December down here in Miami, you used the same physical camera I had to test with for two weeks prior. This camera had pre-release firmware and Leica has since issued two major firmware updates, both of which improved AF performance (speed and accuracy). In fact the latest 1.0.0.16 firmware has noticeably improved on already good speed. Keep in mind that Mark Dubovoy wrote his review based on this latest firmware. I'd suggest trying out the S2 again in its current state to see the difference for yourself. If you are in Miami, I'd be happy to demo it for you.
We've also noticed modest improvement with the S2's focus with the aforementioned firmware updates on our dealer demo units. During the same period the DF body has also seen several firmware updates and has also improved modestly.
Both have much better autofocus than legacy medium format bodies.
Doug Peterson ()
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David,
This camera needs more happy shooters, rather than forum posts. In the end, the only thing which really advertises a camera is people **pro or not pro*** who say"I use this, it works for me".
A good example of this phenomenon is the 5D2, which is far from perfect as a movie cam, but which has established its reputation as a useful and profitable tool by finding a large untapped target audience.. The M8/M9 also have a crowd of people who like the rangefinder experience.
If you can find enough people like Mark or Erwin who enjoy the S2 experience, then the camera will fly. Find users who can benefit - but don't get into a fight with the others. I for one will value Guy's opinion of any camera at least as high as Mark's, because Guy has used a viewfinder to put his kids through college.
Edmund
Edmund,
I have no intention of "getting into a fight" with anyone, nor discounting Guy's opinion. I was merely stating that Guy's experiences were based on a pre-production camera with pre-production firmware from 7 months ago, not on the current shipping version and offered to provide another demo to him so that he could judge for himself.
Many of our customers are very happy with the S2, both pros (yes, those who make their living shooting it) and advanced amateurs, most of whom never go on forums. We've had numerous customers trade in other MFD systems and switch over to the S2 for some of the advantages that Mark talked about in his article. For some, the smaller size and better handling was the most important factor. For others, stellar battery life and good LCD. And, others still, weather sealing or improved AF performance. You get the idea. Each photographer has his or her own priorities and what the final driver is in his/her decision making process will vary from one person to the next. In an ideal world, those who have actually made the decision to go with the S2 would post on forums like this one and share their experiences and reasons why.
David
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Dear David:
Thank you for touching on a very important topic.
I am thankful for two reasons:
1. I have been quite frustrated in the past trying to obtain information directly from Hasselblad. Many inquiries via phone, letter or email have either been left unanswered or simply dropped after a while. The last time I tried to obtain information from Hasselblad (on the focusing system, no less), I could not get anyone's attention, so I ended up resorting to asking the top industrial sales person in the San Francisco Bay Area to please contact the Hasselblad rep on my behalf and then have him try and help us get the information. It still took many weeks of pushing and prodding to get a few simple answers.
If you are the man we need to talk to on Hasselblad technical matters, welcome. I am excited. I would appreciate it if you send me an email with your contact data via the forum. I will then respond in kind and we can begin a direct dialog.
2. The issues that you bring up are certainly important and we should get to the bottom of them. As I mentioned in my article, one good source regarding the Leica autofocus system is a series of technical articles published in Leica Fotografie International. Another source regarding autofocus systems not being continuous was a number of conversations I had directly with PhaseOne/Mamiya technical personnel in their main office in the US. I tried to have the same conversation with Hasselblad and I called several times, but was unable to obtain any information.
My understanding from the technical papers and my direct conversations with at least one MF manufacturer is that the issue is not measuring distances with a phase detection system. You are correct that this can be done continuously. The issue is the mechanics of the lens itself. You need quite a bit of torque to get the focusing system to start moving. The system has inertia, as well as gears and other moving parts. There is a limit as to how "continuous" these parts can move. There is also a limit as to how fast you can apply the brakes and stop the movement. When you put all that together, the mechanisms themselves are not continuous and cannot be moved in infinitesimally small increments. They are "jumpy" and they focus in discrete steps or zones.
So, here is what I have done:
After reading your post, I stayed up late last night until offices opened in Europe. I have already made contact with the chief technical product manager for the S2 in Germany. I have also sent a communication to the Chief Technical Officer at PhaseOne and I am waiting to hear back. If you could contact the equivalent person at Hasselblad, let's get the information directly "from the horse's mouth" at the highest levels at all three companies and share it with our readers.
Best regards,
Mark
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Mark,
I have seen the issue discussed in the description of the original Minolta AF-system, they adjust focusing speeds in some (possibly seven) different steps. I was thinking about this when I read your article. Talking about zones may have been the wrong wording. Lesson learnt, by you I guess.
I really appreciate your efforts to discuss some of the finer aspect of achieving maximal resolution, and also the energy you invest to clear the issues with manufacturers.
Now, some thoughts about testing.
1) We need to be careful with statements that contradict common sense. Take for instance the issue regarding DR. It would be very hard to make a feasible explanation that MFDBs can achieve several stops better DR than DSLRs. For one thing, DR is a technical term, known from signal processing and pretty well defined. The other issue is that would MFDBs have a 6 stop advantage in DR they would be able to work with 6-steps of underexposure. That is like saying that an MFDB would perform at 6400 ISO like a DSLR at 100 ISO, I have not yet seen any evidence that was the case.
2) We can talk about prints. Unfortunately, prints cannot be distributed over the net. Files can be distributed. Why don't you post a few images explaining your experience. Anyone really interested in your writing would be competent to print their own samples. Of course the images demand a lot of bandwidth, but you don't need to release the full image for download.
3) It's nice to use a subject anyone can reproduce. In the great 2006 MFDB shootout the test target included a one dollar (US ;-) bill and Macbeth (sorry X-rite) Mini Color Checker card, anyone can reproduce that!
Now, I'm really appreciate your writing. I'd love to like equipment that you have access to, but rental fees here in Sweden seem to be pretty stiff. So for me it is not feasible to make my own tests. Also it's very nice to have tests done by someone who has a broad experience, like yourself or Michael Reichmann.
Some readers, including myself, have made references to Erwin Puts's tests of the S2, also including the Leica M9. Mr. Puts obviously finds in his tests that the Nikon D3X is superior to the M9 regarding image quality. I have seen some remarks on this forum that discredit him as a camera tester. But what are the issues? Is there anything wrong in his methods??He publishes what he finds and give samples to prove/indicate his findings. What's wrong with that?!
Best regards
Erik
My understanding from the technical papers and my direct conversations with at least one MF manufacturer is that the issue is not measuring distances with a phase detection system. You are correct that this can be done continuously. The issue is the mechanics of the lens itself. You need quite a bit of torque to get the focusing system to start moving. The system has inertia, as well as gears and other moving parts. There is a limit as to how "continuous" these parts can move. There is also a limit as to how fast you can apply the brakes and stop the movement. When you put all that together, the mechanisms themselves are not continuous and cannot be moved in infinitesimally small increments. They are "jumpy" and they focus in discrete steps or zones.
Mark
-
Dear David:
Thank you for touching on a very important topic.
I am thankful for two reasons:
1. I have been quite frustrated in the past trying to obtain information directly from Hasselblad. Many inquiries via phone, letter or email have either been left unanswered or simply dropped after a while. The last time I tried to obtain information from Hasselblad (on the focusing system, no less), I could not get anyone's attention, so I ended up resorting to asking the top industrial sales person in the San Francisco Bay Area to please contact the Hasselblad rep on my behalf and then have him try and help us get the information. It still took many weeks of pushing and prodding to get a few simple answers.
If you are the man we need to talk to on Hasselblad technical matters, welcome. I am excited. I would appreciate it if you send me an email with your contact data via the forum. I will then respond in kind and we can begin a direct dialog.
2. The issues that you bring up are certainly important and we should get to the bottom of them. As I mentioned in my article, one good source regarding the Leica autofocus system is a series of technical articles published in Leica Fotografie International. Another source regarding autofocus systems not being continuous was a number of conversations I had directly with PhaseOne/Mamiya technical personnel in their main office in the US. I tried to have the same conversation with Hasselblad and I called several times, but was unable to obtain any information.
My understanding from the technical papers and my direct conversations with at least one MF manufacturer is that the issue is not measuring distances with a phase detection system. You are correct that this can be done continuously. The issue is the mechanics of the lens itself. You need quite a bit of torque to get the focusing system to start moving. The system has inertia, as well as gears and other moving parts. There is a limit as to how "continuous" these parts can move. There is also a limit as to how fast you can apply the brakes and stop the movement. When you put all that together, the mechanisms themselves are not continuous and cannot be moved in infinitesimally small increments. They are "jumpy" and they focus in discrete steps or zones.
So, here is what I have done:
After reading your post, I stayed up late last night until offices opened in Europe. I have already made contact with the chief technical product manager for the S2 in Germany. I have also sent a communication to the Chief Technical Officer at PhaseOne and I am waiting to hear back. If you could contact the equivalent person at Hasselblad, let's get the information directly "from the horse's mouth" at the highest levels at all three companies and share it with our readers.
Best regards,
Mark
Sorry mark, the buck stops with you here.
The information you presented in your review is flawed and inaccurate. The best place to start would be to acknowledge that and then seek the correct info.
I would have thought that if you were looking for specific info such as focusing mechanisms, then the obvious place to start would be on the forum you are actually reporting for, which is obviously frequented by both Hassy & Phase employees.
Passing the buck does no one any service.
-
I would like to respond to Erik's post regarding autofocus in the hope of clarifying things further.
There seems to be another reason why autofocus systems are not continuous. The reason is as follows:
Basically AF is done through Phase Detection. The light beams are split into two images in the mirror and sent through prisms to the AF sensor. The effect is similar to focusing with a rangefinder. The AF sensor itself is usually only a few pixels high and a few dozen wide. What I think some engineers mean in terms of “steps” or "zones" has to do with the amount of detected sharpness required to be considered in focus. In other words, there is a small range or a "zone" where the system declares that focus is good enough.
Unfortunately, some people may have gotten confused thinking that "zones" means a few zones from close up to infinity. We are talking about many zones here. The more stringent the zone requirement is, the sharper the image will be. What might have been OK for film, or for an old digital back may not be sufficient for a top of the line Medium Format back today. Leica claims it is demanding more precise results from their AF sensor and therefore finer slices (if you want to call them that), in other words more zones.
Interestingly, if an image is farther away, it will have finer peaks and valleys of light on the AF sensor versus a close object. This might explain why long distance AF seems to be less accurate than mid-range AF in many cases. I have had AF failures with both, Hasselblad and PhaseOne systems particularly with distant objects. In my Leica tests, the AF system worked flawlessly. I am sure the Leica AF system would eventually fail if I used the camera for a long time (nothing is perfect!), but my first impression is that it is better than the MF autofocus systems.
Mark Dubovoy
-
Mark,
Thanks for expanding the issue. Actually, I'd suggest that your findings about focusing may be worth another article. Thanks for sharing.
I presume that you have seen the two articles by Joseph Holmes:
http://www.josephholmes.com/news-sharpmediumformat.html (http://www.josephholmes.com/news-sharpmediumformat.html)
http://www.josephholmes.com/news-medformatprecision.html (http://www.josephholmes.com/news-medformatprecision.html)
I would be most interested in your views on Mr. Holmes findings.
Best regards
Erik
I would like to respond to Erik's post regarding autofocus in the hope of clarifying things further.
There seems to be another reason why autofocus systems are not continuous. The reason is as follows:
Basically AF is done through Phase Detection. The light beams are split into two images in the mirror and sent through prisms to the AF sensor. The effect is similar to focusing with a rangefinder. The AF sensor itself is usually only a few pixels high and a few dozen wide. What I think some engineers mean in terms of “steps” or "zones" has to do with the amount of detected sharpness required to be considered in focus. In other words, there is a small range or a "zone" where the system declares that focus is good enough.
Unfortunately, some people may have gotten confused thinking that "zones" means a few zones from close up to infinity. We are talking about many zones here. The more stringent the zone requirement is, the sharper the image will be. What might have been OK for film, or for an old digital back may not be sufficient for a top of the line Medium Format back today. Leica claims it is demanding more precise results from their AF sensor and therefore finer slices (if you want to call them that), in other words more zones.
Interestingly, if an image is farther away, it will have finer peaks and valleys of light on the AF sensor versus a close object. This might explain why long distance AF seems to be less accurate than mid-range AF in many cases. I have had AF failures with both, Hasselblad and PhaseOne systems particularly with distant objects. In my Leica tests, the AF system worked flawlessly. I am sure the Leica AF system would eventually fail if I used the camera for a long time (nothing is perfect!), but my first impression is that it is better than the MF autofocus systems.
Mark Dubovoy
-
Sorry mark, the buck stops with you here.
The information you presented in your review is flawed and inaccurate. The best place to start would be to acknowledge that and then seek the correct info.
I would have thought that if you were looking for specific info such as focusing mechanisms, then the obvious place to start would be on the forum you are actually reporting for, which is obviously frequented by both Hassy & Phase employees.
Passing the buck does no one any service.
Aaron,
Your aggressive tone is uncalled for. In fact since this was first raised by the Hasselblad rep and the issue came to our attention Mark has been aggressively pursuing as much technical information on the subject as he can, directly from senior engineering people at Leica and Phase One / Mamiya. Though in the past getting to high level technical contacts at Hasselblad has proven difficult, maybe now we can do so.
The net result is that when all the data is available and sorted out Mark now intends on writing something comprehensive on the subject, which I hope will benfit all of our understanding on the issue.
What I've learned so far is that while phase detection AF systems do not have "zones" the way that contrast detection systems do, they do indeed focus their lenses in discrete steps, and this is an understood issue in medium format AF design due to such systems' more shallow DOF than 35mm or smaller systems.
So I suggest that the name calling and finger pointing be shelved, and let's all wait to learn more about this subject. Mark Dubovoy is a scientist by profession, with a Phd in particle physics, and therefore well aware of the scientific method and how to apply it to researching and writing up a topic like this.
It appears that we all have something to learn on the subject.
Michael
-
Erik,
Your aggressive tone is uncalled for. In fact since this was first raised by the Hasselblad rep and the issue came to our attention Mark has been aggressively pursuing as much technical information on the subject as he can, directly from senior engineering people at Leica and Phase One / Mamiya. Though in the past getting to high level technical contacts at Hasselblad has proven difficult, maybe now we can do so.
The net result is that when all the data is available and sorted out Mark now intends on writing something comprehensive on the subject, which I hope will benfit all of our understanding on the issue.
What I've learned so far is that while phase detection AF systems do not have "zones" the way that contrast detection systems do, they do indeed focus their lenses in discrete steps, and this is an understood issue in medium format AF design due to such systems' more shallow DOF than 35mm or smaller systems.
So I suggest that the name calling and finger pointing be shelved, and let's all wait to learn more about this subject. Mark Dubovoy is a scientist by profession, with a Phd in particle physics, and therefore well aware of the scientific method and how to apply it to researching and writing up a topic like this.
It appears that we all have something to learn on the subject.
Michael
I completly agree with that statement !
I'm reading from a certain distance, sometimes posting some ideas, good or bad but I must say that I'm astonished by the witches hunting Mark is facing and how sensitive are these subjects.
Lu-La being my first and unique forum, I may be naive and unexperienced, in fact I accept the unexperienced but nothing naive. Yes, there is a lot to learn.
First and for most, in my experience of life at least, mistakes have always been the best masters I ever had.
Instead of barking against someone's mistake, you may want to thank for many reasons.
First, it gives you a magnificent opportunity to show your knowledge with kindness.
Second, from the beginning, Mark has received these 6 stops from the old topic...I knew that would emerge at one point or another.
If you can not forgive mistakes to the others you loose a great knowledge for yourself, and if you can not keep gentle and correct, then you simply loose elegance.
The tones of my posts in this thread reflects my overall feeling about certain content I've read.
A pitty.
Hope we we all learn from that and I thank Mark to give us this oportunity.
-
Wasn't the comment of "the buck stops..." posted by "Aaron" and not "Erik"?
Just hoping to keep "credits" where due.
-
what i dont get, as questioned before , is the dynamic range statement.
Marc: what gives you the idea that any of the current 35 mm ff cameras have a dynamic range of 7 stops at base iso ?
or do you refer to high isos here with the 35mm cams ?
-
Michael,
I think that you are quoting the wrong person. I would never, ever write anything like that.
Also, I actually appreciate Mark's writing. What I have an issue with is more that some of hist statements seem to contradict expectations, at least mine. I have no issue with that but I'd like to see an explanation.
In a follow up posting, Mark essentially says that there are a lot of small things, that add up. I can take that, makes sense.
Also, there are a lot of posters on these forums who use MFDBs and they would certainly not invest in them for vanity. On the other hand, the quest for perfection may go a bit far. You have yourself gone into view camera using Rodenstock HR Digitars. Did the expected advantages materialize? Would be interesting to now.
Best regards
Erik
Erik,
Your aggressive tone is uncalled for. In fact since this was first raised by the Hasselblad rep and the issue came to our attention Mark has been aggressively pursuing as much technical information on the subject as he can, directly from senior engineering people at Leica and Phase One / Mamiya. Though in the past getting to high level technical contacts at Hasselblad has proven difficult, maybe now we can do so.
The net result is that when all the data is available and sorted out Mark now intends on writing something comprehensive on the subject, which I hope will benfit all of our understanding on the issue.
What I've learned so far is that while phase detection AF systems do not have "zones" the way that contrast detection systems do, they do indeed focus their lenses in discrete steps, and this is an understood issue in medium format AF design due to such systems' more shallow DOF than 35mm or smaller systems.
So I suggest that the name calling and finger pointing be shelved, and let's all wait to learn more about this subject. Mark Dubovoy is a scientist by profession, with a Phd in particle physics, and therefore well aware of the scientific method and how to apply it to researching and writing up a topic like this.
It appears that we all have something to learn on the subject.
Michael
-
Sorry, my comment should have been directed at Aaron, not Erik. My mistake, now corrected.
Michael
-
Hi,
I'm also asking the same question.
In my view there is a technical definition of DR (Full well capacity/Read noise) that may be not relevant to photography. In real photography it is my understanding is that shot noise dominates and thats about square root of detected photons. The number of detected photons should be proportional to the size of the sensor. So doubling the surface of the sensor would give about half a stop, but I may oversimplify that.
In addition I feel that the discussion is complicated by the fact that we would have most noise in the dark parts and tonality would normally be compressed in the darks as we apply some kind of shadow compression (toe characteristics) in both image processing and printing.
Best regards
Erik
what i dont get, as questioned before , is the dynamic range statement.
Marc: what gives you the idea that any of the current 35 mm ff cameras have a dynamic range of 7 stops at base iso ?
or do you refer to high isos here with the 35mm cams ?
-
Great!
Still friends?!
Erik
Sorry, my comment should have been directed at Aaron, not Erik. My mistake, now corrected.
Michael
-
what i dont get, as questioned before , is the dynamic range statement.
Marc: what gives you the idea that any of the current 35 mm ff cameras have a dynamic range of 7 stops at base iso ?
or do you refer to high isos here with the 35mm cams ?
I don't have a dog in this hunt but I don't understand these tests or comparisons.
No knock on Mark, but a photo of someone's backyard doesn't tell anyone very much.
The focus thing has been on going with digital, since we could see the images at 100% and though I have no doubt that digital is more difficult to achieve exact focus, I have or have used about every camera made and I can tell you that autofocus on anything (except maybe a Nikon D3/D700) is always very, very, very subject dependent.
What is in dead focus for two hours can change in a heart beat with different subjects, lighting and/or just stepping back 6 ft. and I've got about 20 bazillion files to prove it.
As far as a dslr only has 6 stops of range I'm not so sure that one flies. I've shot medium format next to dslrs for a few years and I see a difference in the files, sometimes in depth, or color, sometimes in shadow detail and sharpness, but never have I seen a 7 stop advantage from any camera system, or better put a 7 stop disadvantage.
What I don't understand about Leica, (and I wish them well) is how the hell they sell these cameras in the first place given the fact that lenses are very late and tethering by all accounts is enormously slow. If Leica wants to shake the rich dentists paint brush I'd suggest addressing both of these points.
Still, what I'd love to see on any comparison is a test like the Zaguto people funded. Sure it may have some bias given Zaguto sells bits for dslrs, but overall when you fill the room of "working" professionals I doubt seriously if everyone there has any agenda other than to find out the facts.
http://www.zacuto.com/shootout (http://www.zacuto.com/shootout)
That's the kind of test I'd like to see and would go a long way to making these threads more fact based than conjecture.
IMO
BC
-
Hi,
I'm also asking the same question.
In my view there is a technical definition of DR (Full well capacity/Read noise) that may be not relevant to photography. In real photography it is my understanding is that shot noise dominates and thats about square root of detected photons. The number of detected photons should be proportional to the size of the sensor. So doubling the surface of the sensor would give about half a stop, but I may oversimplify that.
In addition I feel that the discussion is complicated by the fact that we would have most noise in the dark parts and tonality would normally be compressed in the darks as we apply some kind of shadow compression (toe characteristics) in both image processing and printing.
Best regards
Erik
Erik,
The biggest problem IMO, is that strick measurements are not applicable in real field photography and I would like to explain why.
The scientists measurements are giving a very small advantage in DR for the MF backs, that's one part.
1/2 - 1 stop is very little, almost insignificant and at the same time important.
My personal experience of designer in some advertising adgencies during many years, I have spent time in the post production task and the differences between files are clear.
The field, is that MF gives you a lot more room than 35mm, even an old 22mp MF. The difference is not little but huge, but only when you need to play on the extremes.
That is indeed more noticiable when you need to push or extract a lot from your file. Not only it gives you room, but the quality of this "room" is much cleaner at based isos,
specially in shadows. The result is that for certain applications and in extreme PP, MF is simply way ahead. For how much?
I mean, how much suggestives DR stops would I give to MF when it comes to the real task? In my experience I can see at least 4 stops difference in applications before the image starts to fall appart.
It's amazing what you can recuperate with these backs. (ok, I know that normally if we do the job right we shouldn't have to, but...)
Maybe it is not 6, but it is certainly not 1.
According to the focusing, (still do not understand why things are not in focus for some) you center a lot the comments on the lens, but with the resolution of the current backs, that is just a small pasrt of the equation.
Mirror is a real problem (I suspect to be the biggest issue), tripods also and the way you handle the lightning in the case of controled sources etc...
Correcting manually after re-framing.
Also, I've seen pros that often go over closing their diaph. Beleive it or not but it is more current that you may think. Shooting at f22 and then complain about the lack of sharpness quality...
Cheers.
-
Re. AF, the question is not only what can the camera measure, it is also what can the lens be set to by the camera's AF. In other words the design of the actuator on each lens comes into play.
I do think that Mark's review is a paper which the referees would like revised ....when I was organizing conferences, we would simply ask an author to take the referres's views into account, and the paper would usually get improved.
Edmund
in my professional world it would have been rejected by every knowledgable referee.
peter
-
......snip.........
Maybe it is not 6, but it is certainly not 1.
.......snip........
Cheers.
Maybe because I worked transparency film for so long that I find digital to be flatter than the economy in Greece, but even if there is a 4 something stop advantage in medium format (I really don't believe this), or almost medium format or whatever medium format is called today, there is also a thing called working in a professional manner. We have foam core, lights, all sorts, silks, shiny boards and even if that's not possible with digital the ability to shoot multiple exposures, and blend them.
In fact unless your shooting at base iso I know my digital backs have less shadow performance than the dslrs I use. At base iso there all very close, though I will be the first to admit the lack of an aa filter, the larger format does allow for some easier post production than most dslrs, though the difference is something I see, rarely if ever does the paying customer notice or even care.
There is a lot of reasons to shoot medium format and the overall sharpness at low iso with a lot of light is one of them, given the amount of post abuse we apply after a shoot, but to report a hand held camera to completely out performs everything in it's class somewhat surprises me given the state of readiness the S-2 is at and given the fact that Phase and Hasselblad (more so hasselblad on the lens side) has a lot of experience at this price level.
But all of this is a mute point other than it seems to me the Leica review had a slant towards Leica. Maybe the focus is better, but it would take a lot of days, a lot of frames and a lot of subjects for me to actually say that about any camera. Maybe the lenses are Leica steller and 3d ish but once again I'd like to see this in real but tightening money on the table production.
As far as focusing goes, especially with "medium" format, or any camera, I suggest a tripod because focus will improve by 90%, no matter what camera your shooting.
IMO
BC
-
My personal experience of designer in some advertising adgencies during many years, I have spent time in the post production task and the differences between files are clear.
The field, is that MF gives you a lot more room than 35mm, even an old 22mp MF. The difference is not little but huge, but only when you need to play on the extremes.
Can we at least agree once for all that not all DSLRs are equal DR wise? Why should they be when technology obviously plays a more important role than basic physics in influencing the quality of the output of a sensor?
I had the chance to play recently with 5DII files (shot by a pro for my wedding incidently) and was surprised by the amount of noise at low ISO in these files. If your assessment of DSLR is based on a 5DII then I totally understand how you feel about them.
The D3x is simply in a class of its own from that standpoint. This is both measured and seen in the files/prints. I am not claiming that the D3x is at MFDB level, just that they are clearly head and shoulder above the other DSLRs as we speak. I really hope that Sony and Canon do a better job in their next generation camera so that we can finally look objectively at the amazing job Nikon did with the D3x without brands afinity/relationships coming in the way.
Considering that back manufacturers claim that the main reason why they are superior DR wise is the quality of the circuitery and attention paid to details, there is no reason to think that DSLR manufaturers with the right skills and much more cash could not do a good job also. Incidently, that is exactly what Nikon claim they did. unfortunately, these forums do not have any Nikon representative coming to exlain us what they did and why it is reasonnable to believe their claims.
Cheers,
Bernard
-
i work since years as well with mf and 35mm, long and much enough that the choice i take is driven by practical / aesthetical thoughts not by status or price / quality believes and i think with 1 stop difference between current 35mm ffs and current mf backs we are more on the reality side ( and even this depends a lot on the light source ).
btw. i use a lot the 5dmk2 since the new shift lenses are out and no complains about noise so far from my side. its not perfect but a very reliable and professional tool, prints can look simply great , if shot and postprod with the right hands.
for me way more unusable are any kind of green magenta shifts, which still seem to be common with the kodak sensors if no constant white references are taken ( talk about the M ). but never i was reading in any test about that. what a pity.
-
Aaron,
Your aggressive tone is uncalled for. In fact since this was first raised by the Hasselblad rep and the issue came to our attention Mark has been aggressively pursuing as much technical information on the subject as he can, directly from senior engineering people at Leica and Phase One / Mamiya. Though in the past getting to high level technical contacts at Hasselblad has proven difficult, maybe now we can do so.
The net result is that when all the data is available and sorted out Mark now intends on writing something comprehensive on the subject, which I hope will benfit all of our understanding on the issue.
What I've learned so far is that while phase detection AF systems do not have "zones" the way that contrast detection systems do, they do indeed focus their lenses in discrete steps, and this is an understood issue in medium format AF design due to such systems' more shallow DOF than 35mm or smaller systems.
So I suggest that the name calling and finger pointing be shelved, and let's all wait to learn more about this subject. Mark Dubovoy is a scientist by profession, with a Phd in particle physics, and therefore well aware of the scientific method and how to apply it to researching and writing up a topic like this.
It appears that we all have something to learn on the subject.
Michael
Michael,
Perhaps my tone was a little agressive, my apologies to Mark, this is not life and death stuff.
Aaron.
-
Maybe because I worked transparency film for so long that I find digital to be flatter than the economy in Greece
Agreed. Thank god we don't have to be stuck with one "emulsion" for any given shot. The manufacturer's defaults take all of a few seconds to override. You can turn a high bit-depth high-DR medium format raw file into a transparency film look or a muted color negative etc etc etc and still have all the proper tonal transitions and detail (or lack there of). Better to start with a file with great highlight/shadow headroom and then increase contrast 10 or 20 points than to start with a file with clipped highlight and shadow detail and then try to recover or fake detail/grain/color-accuracy/transitions in the highlights and shadows.
Doug Peterson ()
__________________
Head of Technical Services, Capture Integration
Phase One, Leaf, Cambo, Canon, Apple, Profoto, Eizo & More
National: 877.217.9870 | Cell: 740.707.2183
Newsletter: Read Latest or Sign Up (http://www.captureintegration.com/our-company/newsletters/)
RSS Feed: Subscribe (http://www.captureintegration.com/2008/08/11/rss-feeds/)
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Personal Work (http://www.doug-peterson.com/)
-
Can we at least agree once for all that not all DSLRs are equal DR wise? Why should they be when technology obviously plays a more important role than basic physics in influencing the quality of the output of a sensor?
I had the chance to play recently with 5DII files (shot by a pro for my wedding incidently) and was surprised by the amount of noise at low ISO in these files. If your assessment of DSLR is based on a 5DII then I totally understand how you feel about them.
The D3x is simply in a class of its own from that standpoint. This is both measured and seen in the files/prints. I am not claiming that the D3x is at MFDB level, just that they are clearly head and shoulder above the other DSLRs as we speak. I really hope that Sony and Canon do a better job in their next generation camera so that we can finally look objectively at the amazing job Nikon did with the D3x without brands afinity/relationships coming in the way.
Considering that back manufacturers claim that the main reason why they are superior DR wise is the quality of the circuitery and attention paid to details, there is no reason to think that DSLR manufaturers with the right skills and much more cash could not do a good job also. Incidently, that is exactly what Nikon claim they did. unfortunately, these forums do not have any Nikon representative coming to exlain us what they did and why it is reasonnable to believe their claims.
Cheers,
Bernard
Bernard,
I'm aware of that Nikon. What you point has always been a Nikon's strengh. Yes, in agencies 95% of the files where Canon's from 1D saga. (I quit before the 5D2).
About my 4 stops, you'll have noticed that I wrote my "sugbectives stops". 1 stop is considered as the reasonable norm.
I have another experience when it comes to PP.
As I pointed, the recuperation capability or headroom as you say in english, at based isos because above 400 forget it, is much more than that and I claim 4 stops non official .
BC certainly point a truth: we can acheive almost what we want today when handled by pros, with any gear.
I also find digi flatter than the greek economy and I find these DR and focus preocupation completly exacerbate.
In fact, I'm working now on trying to restrain my DR for certain works that I hope I'll be able to put on line after this summer.
Less DR and autofocus would not be bad, sometimes and at least for me.
PS 1: BC, I like the "snip", "snip"...is it the sound of the Canon's curtain or the Contax? The Leica does "clow" clow", but they are German.
PS 2: Hey, now that you send your retouchings, have you already forgot about the oscurs texan days when you had to do the task by yourself?
But I'm sure you would love again the MF files if you where a simple designer.
SRV was playing the Fender with lamp amp.
-
for me way more unusable are any kind of green magenta shifts, which still seem to be common with the kodak sensors if no constant white references are taken ( talk about the M ). but never i was reading in any test about that. what a pity.
I honestly think that only few people see it. (not because it's just subtile... but most people simply don't expect a color shift to be there... so they don't see it).
-
I honestly think that only few people see it. (not because it's just subtile... but most people simply don't expect a color shift to be there... so they don't see it).
it looks like.
and from that point on i dont understand what about all this discussions are good except to create myths
about thats the camera which counts if a photograph looks good or not.
and even if such fundamental weak points would be seen and discussed as well in our forums and tests ( so long till the manufactors would be pressed enough to change their products to perform as they should do it ) it would not change that
a 10% better taken motif outperforms any given "x" mp more resolution.
a slightly better selected moment of the shot or a slightly better light counts by far more in the final image
as any 0,X stops higher dynamic range.
-
and from that point on i dont understand what about all this discussions are good except to create myths
about thats the camera which counts if a photograph looks good or not.
and even if such fundamental weak points would be seen and discussed as well in our forums and tests ( so long till the manufactors would be pressed enough to change their products to perform as they should do it ) it would change that
a 10% better taken motif outperforms any given "x" mp more resolution.
a slightly better selected moment of the shot or a slightly better light counts by far more in the final image
as any 0,X stops higher dynamic range.
so true!
-
Agreed. Thank god we don't have to be stuck with one "emulsion" for any given shot. The manufacturer's defaults take all of a few seconds to override. You can turn a high bit-depth high-DR medium format raw file into a transparency film look or a muted color negative etc etc etc and still have all the proper tonal transitions and detail (or lack there of). Better to start with a file with great highlight/shadow headroom and then increase contrast 10 or 20 points than to start with a file with clipped highlight and shadow detail and then try to recover or fake detail/grain/color-accuracy/transitions in the highlights and shadows.
Doug Peterson ()
__________________
Head of Technical Services, Capture Integration
Phase One, Leaf, Cambo, Canon, Apple, Profoto, Eizo & More
National: 877.217.9870 | Cell: 740.707.2183
Newsletter: Read Latest or Sign Up (http://www.captureintegration.com/our-company/newsletters/)
RSS Feed: Subscribe (http://www.captureintegration.com/2008/08/11/rss-feeds/)
Buy Capture One at 10% off (http://www.captureintegration.com/phase-one/buy-capture-one/)
Personal Work (http://www.doug-peterson.com/)
I arrived to the same conclusion as you, Doug.
In my desire to put the DR into a box, I mean by that to reduce it, my first way has been to clip from capture. But this was not the right way to do because it was too unpredictible. Digital is not film. As you point, better to have headroom and then I get rid of it in PP.
I've always been critic with MF in terms of usability, specially with the lcd, but I have nothing to complain in terms of IQ.
I like when I move the cursor to the left or right in capture and the image is not falling appart. It simply stands still.
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I know this is out of topic, but intrigued by the BC avatar, I went to the Dukes of Hazzard website to try to understand.
But I don't understand anything really. I don't get it.
And why General Lee car appears all the time in that web page?
Does an American citizen could resume to a European the importance of Cooter's in your culture?
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I know this is out of topic, but intrigued by the BC avatar, I went to the Dukes of Hazzard website to try to understand.
But I don't understand anything really. I don't get it.
And why General Lee car appears all the time in that web page?
Does an American citizen could resume to a European the importance of Cooter's in your culture?
Fred
I well remember watching the Dukes series; it was a fascinating look into the imaginary life of the American boondocker. It also represented something almost aspirational - don't laugh - what with its CB radio etc. which, believe it or not, was banned in the UK for quite some time, as were the pirate radio stations, of which Radio Caroline (North and South) was my favourite. Many an otherwise lonely night in the darkroom was helped along by the Mamas and the Papas chanting about their 'darkest hour' being 'just before dawn'! Too bloody true! Another one that I loved, Radio Scotland, was local, and it was on when they announced that Elvis had left the building. Also, there was an ad for a modelling agency on it for a while, that I followed up and which led to my first contact with a pro version (as raw as myself at the time) of the genre from whence it all (my real photo life) began. So thanks, pirates.
But the Dooks' car: also a huge part of the US dream for other people. Living in India for some years I was quite used to the sight of US wheels of the 40s - early 50s; back in the UK (a song there?) maybe all folks saw of them was around USAF bases and compared with the junk that we produced in Britain and the prices of said rubbish when compared to the US home-buys, no wonder we thought the US a promised land. Somehow, that Ford Consul was never going to look cool with a Union Jack on the roof. The Mini graced some such motifs during the Carnaby Street era in the home-grown version of self-expression but it was something quaint rather than macho, art born of poverty.
I guess that America still remains a bit of a dream for non-Americans; we have been raised on the Hollywood version of reality and it was years before I, for one, accepted that not all Americans had V8s, swimming pools and lived in houses with white fences with a barn and a horse at the back. All cowboys played the guitar, had balls of steel that could withstand leaping down into a saddle from extraordinary hights (strong nags, too!) and, best of all, nobody ever had to work. Well, perhaps not best of all; best of all was that all the girls were fantastically beautiful, passed the days in school, cafés or flower shops, appeared to have no guile whatsoever and anyone could just walk up and stand a pretty good chance of scoring! The one bad thing: we all had to learn how to walk like Robert Mitchum. It was half-way easier for me, being called Robert, but that half was the only bit that worked.
I suspect that some large percentage of the US still quietly believes parts of the same dream: you'd have too - why else continue the battle against the odds? For the rest of us - maybe disillusion sets in earlier, not a happier choice. Obviously enough.
But without dreams we might as well emulate the lemming.
Rob C
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How come we are talking about 35mm vs MF again and DR?
Anyway, to get back on track. Thanks for your reply Mark.
I'm in Italy today so wont be able to give you a proper response, so please bear with me until tomorrow!
I certainly have stuff from the horses mouth regarding our AF operation. Of course it would not be right for me to comment on Leica or any other manufacturers systems further.
Cheers,
David.
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How come we are talking about 35mm vs MF again and DR?
Anyway, to get back on track. Thanks for your reply Mark.
I'm in Italy today so wont be able to give you a proper response, so please bear with me until tomorrow!
I certainly have stuff from the horses mouth regarding our AF operation. Of course it would not be right for me to comment on Leica or any other manufacturers systems further.
Cheers,
David.
yes.
one point among various others which are related only to mf type sensors and cameras.
( ... magenta-green should be a well known keyword for your too , although these kodak sensor designs are used in 35mm by the M and formerly the kodak 14n/slr as well )
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..........................................
I had the chance to play recently with 5DII files (shot by a pro for my wedding incidently) and was surprised by the amount of noise at low ISO in these files......................
Cheers,
Bernard
Congratulations Bernard & wish you many joys outside of our L-L bubble.
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yes.
one point among various others which are related only to mf type sensors and cameras.
( ... magenta-green should be a well known keyword for your too , although these kodak sensor designs are used in 35mm by the M and formerly the kodak 14n/slr as well )
I've seen horrible xtreme mag-green with the 14n I must say, but that was some years ago.
Back with this Leica S2 article, a point I regret that has not been discussed, is the dslr design choice.
The S2 proposal makes me perplex on that. I don't understand why it is not possible to combine both worlds???
I mean, a dslr design and usability, but with removable back.
Sinar did something in that way with the M, although this Sinar is pretty big.
[attachment=22872:11791683...inar_m_b.jpg]
The biggest problem I see with this Leica, is that it will not be fast enough to please the dslr users, and not versatile enough to please the MF users.
Even if they improve the tether and the lens range.
When sensor is obsolete, and they are quite fast, the all body will have to be buy again, but this is another story than upgrading the C Mark...
The Pentax can handle that because it is much cheaper.
But, why MF manufacturers are not "wilder" when it comes to designing their bodies and their backs lcd?
The Sinar M design style, on diet and with a powerfull lcd and connections will truly be a winner.
But the sad story, is that such a system will probably be done by the "big boys" before MF brands will have reacted on time.
And when it's too late it's too late.
I hope that Leica and others will put their designers on the drawing board very soon and finally come with more drastic solutions.
Edit: Rainer, I've seen after writing my post that you are using the Sinar M. Coincidence? Anyway, I'd like you to comment about your feeling on this design.
Do you feel a better usability than with other MF cameras ? the M being let's say a modular philosophy and closer to a dslr design.
That would be interesting to have your thoughts. Thanks.
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yes.
one point among various others which are related only to mf type sensors and cameras.
( ... magenta-green should be a well known keyword for your too , although these kodak sensor designs are used in 35mm by the M and formerly the kodak 14n/slr as well )
I am not sure I understand the point of your post?
Those kodak designs are well behind what they produce today.
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I am not sure I understand the point of your post?
Those kodak designs are well behind what they produce today.
so no more color shits visible between the right and the left side of the frame if e.g. an even grey colored wall is photographed, without that you are applying a white reference ?
with shift cameras i dont see this a big problem because now ( after many many years ) all have a working solution integrated in their software to apply these white references in a more or less fluid workflow ( although of course it would be better if there would be NO need for this step as it is with canon/nikon/sony sensors ) but cameras as the M which provide dng files even does not allow you the possibility to correct the files afterward in that way.
several M users commented this issue to me, these shift in general are very well known for me since the first generations of kodak sensors, as far as i know till today at least for a part of their product line- do not know the youngest 50/60 mp sensors.
maybe i am wrong with this and you use sensors in your h50/60 behave different, but even if so please have in mind how many years H has been sold this color shifting sensors without providing even any software solution to remove these shifts ( before your new software came out 1 year ago or so ).
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so no more color shits visible between the right and the left side of the frame if e.g. an even grey colored wall is photographed, without that you are applying a white reference ?
with shift cameras i dont see this a big problem because now ( after many many years ) all have a working solution integrated in their software to apply these white references in a more or less fluid workflow ( although of course it would be better if there would be NO need for this step as it is with canon/nikon/sony sensors ) but cameras as the M which provide dng files even does not allow you the possibility to correct the files afterward in that way.
several M users commented this issue to me, these shift in general are very well known for me since the first generations of kodak sensors, as far as i know till today at least for a part of their product line- do not know the youngest 50/60 mp sensors.
maybe i am wrong with this and you use sensors in your h50/60 behave different, but even if so please have in mind how many years H has been sold this color shifting sensors without providing even any software solution to remove these shifts ( before your new software came out 1 year ago or so ).
Lens cast correction has been available 3 years plus in Hasselblad software. Can we get back on topic?
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Ok, I have found myself with a bit of airport time so will respond to Mark and Michael in one post.
From Mark...
My understanding from the technical papers and my direct conversations with at least one MF manufacturer is that the issue is not measuring distances with a phase detection system. You are correct that this can be done continuously. The issue is the mechanics of the lens itself. You need quite a bit of torque to get the focusing system to start moving. The system has inertia, as well as gears and other moving parts. There is a limit as to how "continuous" these parts can move. There is also a limit as to how fast you can apply the brakes and stop the movement. When you put all that together, the mechanisms themselves are not continuous and cannot be moved in infinitesimally small increments. They are "jumpy" and they focus in discrete steps or zones.
I expect the manufacturer you are talking about does not use motors inside the lens to drive the focussing optics but rather a motor inside the camera body? Hasselblad uses motors inside the lens, so a larger lens can use a larger motor etc etc.
The advantage of the motor inside the lens is that there is no mechanical connection needed to be made when attaching the lens to the camera body. The small armature that protrudes from the lens mount to drive the mechanics I would expect to have some degree of mechanical slop, albeit a small amount.
Therefore as you get to the far range of focus and smaller amounts of movement on the optics need to be applied then the mechanical intolerance (if thats a word) would render it difficult to make precise steps and therefore have a jumpy effect with the result be a loss in finite focussing. So I assume this is the conclusion from your conversations with Mamiya? Please correct me if I am wrong.
The stepper motors in the H lenses do not suffer from this issue. If you connect an H camera to our Phocus software you can see this yourself. Using the camera control tool, you can manipulate the focus using the + and - buttons. Hold down the Cmd key whilst clicking these buttons and this will give you an extremely fine focus. ie they can be moved in infinitesimally small increments.
I hope that clears it up from my end.
If you wanted to research further, what you could investigate is when the AF drive goes back at forth at some point the camera will decide “Im in focus within my factory set tolerance”. I cannot find any data from Canon and Nikon which describes this tolerance. Perhaps it is mentioned in the Leica articles?
The tolerance for us does not change at either end of the focussing scale.
From Michael...
What I've learned so far is that while phase detection AF systems do not have "zones" the way that contrast detection systems do, they do indeed focus their lenses in discrete steps, and this is an understood issue in medium format AF design due to such systems' more shallow DOF than 35mm or smaller systems.
I hope with my words above I have tried to describe that this is not the case with the Hasselblad AF system.
From my work eons ago as a motorsport photographer (Using Manual Focus!! Ugh!!) I would expect a Nikon / Canon 400mm/500mm+ does not have very much DOF at the infinity scale. Perhaps it is interesting to know from our readers if they feel the 35mm systems fail at infinity focussing?
To close, I am sorry to hear if you felt that it was hard to get in touch with someone at Hasselblad. However, I have been a pretty active poster here for a couple of years and am only a PM away.
Best Regards,
David
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Edit: Rainer, I've seen after writing my post that you are using the Sinar M. Coincidence? Anyway, I'd like you to comment about your feeling on this design.
Do you feel a better usability than with other MF cameras ? the M being let's say a modular philosophy and closer to a dslr design.
That would be interesting to have your thoughts. Thanks.
i have a contax setup and a sinar M setup, both with all lenses. the contax is still my favourite body because its so handy and nice small lenses, but i never use af with it- anyway with the sinar either.
the sinar M is more modern and with the small battery it can be way better used as with the large battery on your photo. the 28mm rodenstock is stunning, but also the other lenses are great,- maybe the best lenses i have used. the 40mm shows a tick of CA, but all are sharp even wide open, which arent the contax which want to be stopped down for maximum sharpness.
the display on the newer emotion 75 backs is nice as well . not as big as leaf and hassy but very good readeable even in sunlight. the applying of the white files in eXposure works now as i have advised it to sinar two years ago. very practical with great result and convenient workflow.
to be honest i rarely use non shiftable systems so both cameras have a quiet life and are rarely used. its a pity, but for my work ( except for aereals and long tele lenses ) i only use shift lenses, now 50% the canon and 50% the artec,- which is a great camera,-( no wonder that i say that right? ), beside the fact the it was made together by sinar and my person i think its really an intelligent solution for architecture photography which provides a great workflow on site,- i still prefer the work with the artec over the mostly lcd based work with the canon and i prefer it for 1000% for any viewer based solution or any solution which requires to unmount the ground glass.
in practical conditions i have shot now several projects side by side with canons and the artec and choosed the files afterwards only selecting these which i liked more ( color rendering , moiree, resolution , general appearance and so on. ) i end up with mostly 50% for each system. thats a funny result beacuse it sais if i would use only 1 system i could take the one or the other ending up with a similar end result. have to say that i stitch often with the canon / pentax lenses and i dont do it often with the artec, teher is no need in terms of resolution and the shift ways are shorter.
thinking sometimes in buying a P65 or an A10, i am no resistant at all against this hi-tech addiction as you can easily see if you check my equipment and what i did in the past to get usuable images ( i mean also that not everyone was working in develloping soft and hardware, motivated nearly only from his own perfectionism ). but i am not convinced .... i have a serial of big exhibitions in museums in front of me in several parts of the world, the prints i make will not be sooo huge as it is so modern right now, i will print 100 x 145 cm and some images 100 x 220cm,- and these are looking great with my emotion backs and also with ( right- left or up- down stitched ) canon images. as soon i will believe that my images will gain in any way from higher resolution or some ( at least claimed ) higher dr i will run and get such tool.
for my architecture work, which hardly could be more demanding in terms of my clients and objects i dont see any need for more resolution, but i see each time again the need for highest concentration, a lot of time to spend for the right light, a lot of tools and efforts to get the right perspectives and a convenient and pleasing workflow which does not hinder me creating my images.
long answer - of topic - but i hope not a too big problem to fade away a bit.
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Lens cast correction has been available 3 years plus in Hasselblad software. Can we get back on topic?
no we cant, but soon.
if i am not completely wrong phocus was announced end of may 2008 for V1 so we get two years at least.
how many years before have been sold cameras and sensors without any possibility to correct these casted files?
and i would be pleased if you answer this my question from my post, referring to the newest generation of kodak sensors in your 39/50/60 mp backs:
is there no more color shift visible between the right and the left side of the frame if e.g. an even grey colored wall is photographed, without that you are applying a white reference ?
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i have a contax setup ad a sinar M setup, both with all lenses. the contax is still my favourite body because its so handy and nice small lenses, but i never use af with it- anyway with the sinar either.
the sinar M is more modern and with the small battery it can be way better used as well as with the large battery on your photo. the 28mm rodenstock is stunning with it, but also the other lenses are great,- maybe the best lenses i have used. the 40mm shows a tick of CA, but all are sharp even wide open, which arent the contax which want to be stopped down for maximum sharpness.
the display on the newer emotion 75 backs is nice as well . not as big as leaf and hassy but very good readable even in sunlight. the applying of the white files in eXposrue works now as i have advised it to sinar two years ago. very practical with great result and convenient workflow.
to be honest i rarely use non shiftable systems so both cameras have a quiet life and are rarely used. its a pity, but for my work ( except for aereals and long tele lenses ) i only use shift lenses, now 50% the canon and 50% the artec,- which is a great camera,-( no wonder that i say that right? ), beside the fact the it was made together by sinar and my person i think its really an intelligent solution for architecture photography which provides a great workflow on site,- i still prefer the work with the artec over the mostly lcd based work with the canon and i prefer it for 1000% for any viewer based solution or any solution which requires to unmount the ground glass.
in practical conditions i have shot now several projects side by side with canons and the artec and choosed the files afterwards only selecting these which i liked more ( color rendering , moiree, resolution , general appearance and so on. ) i end up with mostly 50% for each system. thats a funny result beacuse it sais if i would use only 1 system i could take the one or the other ending up with a similar end result. have to say that i stitch often with the canon / pentax lenses and i dont do it often with the artec, teher is no need in terms of resolution and the shift ways are shorter.
thinking sometimes in buying a P65 or an A10, i am no resistant at all against this hi-tech addiction as you can easily see if you check my equipment and what i did in the past to get usuable images ( i mean also that not everyone was working in develloping soft and hardware, motivated nearly only from his own perfectionism ). but i am not convinced .... i have a serial of big exhibitions in museums in front of me in several parts of the world, the prints i make will not be sooo huge as it is so modern right now, i will print 100 x 145 cm and some images 100 x 220cm,- and these are looking great with my emotion backs and also with ( right- left or up- down stitched ) canon images. as soon i will believe that my images will gain in any way from higher resolution or some ( at least claimed ) higher dr i will run and get such tool.
for my architecture work, which hardly could be more demanding in terms of my clients and objects i dont see any need for more resolution, but i see each time again the need for highest concentration, a lot of time to spend for the right light, a lot of tools and efforts to get the right perspectives and a convenient and pleasing workflow which does not hinder me creating my images.
long answer - of topic - but i hope not a too big problem to fade away a bit.
Very interesting Rainer. Thanks for sharing your thoughts.
I also agree that with the Canon, enlargements of 1m-2m are perfectly good. I find the deth a little "washed" if I can use this expression and tend to add grain in PP to compensate, but that is the Canon's look anyway.
Also in the same thoughts as yours about the upgrading to the extremes. I'm obviously not in a position to purchase a P65, but I already asked myself that question anyway and I think I would not upgrade to more than 40thish MP even if I had the B.Gates bank account. I understand however why some are doing it.
About your statement I painted red, I could not agree more. That is indeed where MF manufacturers will have to concentrate their efforts.
This has been discussed and claimed quite a lot on this forum and I hope you guys (David, Doug) are writting user's reports to the people who take the decisions at Phase, Hassy etc...
But there is also another factor that has been hardly discussed here and I'll try to explain the best I can with my English.
Take the making-off (s). Do you imagine the crane, the helicopter, all that machinery with a little dslr? Something would look wrong. What I'm talking about is the domain of the image and its impact.
All these devices are heavy to deal with, but they transmit something to client. That is not a minor factor IMO.
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Just to go back to the AF of the S2 and DF bodies just to clarify a few points. First I have not shot the absolute latest version of the S2 firmware so some things may have changed but what was left out here is the DF will shoot continuous focus and the S2 will not ( again this may have changed but I don't think so). So back when Jack and I did the review of the S2 and P40+ the S2 did feel faster to lock in on the center point over the DF but it was kind of weird as it did not refocus when you released the the half press and readjusted as easily as the DF body did. I also felt the DF was actually better for a lot of work where continuous was needed . In this thread I am talking about the Sensor Plus but if you look down in the article I was shooting runway with a 300mm on a monopod and using continuous focusing on the DF and it it really did a nice job of following the model and obviously the worst movement for AF is something coming straight at you and I did not miss much especcially with a 300mm AF lens of older design ( Phase there is a hint here ). Now granted not Canon/Nikon speed but it works very well here is a link if interested. http://forum.getdpi.com/forum/showthread.php?t=13379 (http://forum.getdpi.com/forum/showthread.php?t=13379)
Now I do not know the tech. data behind the scenes of levels of focus ability as I do not have that data from the OEM's and obviously I can't speak for the Hassy system in here as I am still waiting to test the HD4/40 system. Anyway this is real world and I also found the DF was a little better in low light but it was very close and both systems where very good in low light which is a big bonus in MF. The S2 does a very nice job of focusing but I had a hard time with it in the beginning until I switched it to manual than used a rear button for AF which I really liked much more. I do talk about this early on in this review http://forum.getdpi.com/forum/showthread.php?t=12243 (http://forum.getdpi.com/forum/showthread.php?t=12243). Now I will not speak of Marks review here since he also has shot the S2 with a later version of the S2 firmware but these systems are pretty darn close, not sure I would say they are worlds apart but yes some differences for sure and the S2 does feel quicker but the lenses are also bigger and heavier and in the working with them all things being together as a package not sure I would say one has a clear advantage over the other but I will say the are far better than the AFD III, II and AFD. Again I am sure the new Hassy focus system is on par as well. It actually may have a slight advantage because of the different AF system employed now. That is a guess on my part since I have not tried it but nice reports on it for sure. Bottom line none of them are in the 35mm league and still for the most part are center point focusing. I know I do very well with the DF and I liked the S2 on it's end once I figured how to work it to my taste, obviously this will differ among users. But as many of us know in use most of the time we are in manual mode. I NEVER shot a advertising project with AF in all my 35 years, so I have to laugh a little because I know many shooters are the same as me stick it on manual and get to work. Sorry I just have never completely trusted any AF system on the planet and a very simple logical reason they can't think. They have no idea what is going on in your brain and what you are after. End of day though the modern MF bodies are much better than even a year ago but they can all be better as well.
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Thanks for the real world info Guy.
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.... Perhaps it is interesting to know from our readers if they feel the 35mm systems fail at infinity focussing?
Best Regards,
David
I would say that it depends a lot on what is on this infinity.
I have experience with the Canons (but not the last generation) and the Pentax. I came to the conclusion that human brain+practise+intuition can smokes any of these AF (oh my god what I just wrote now... )
and I'm focussing now 1000% manual with green light confirm if there is. I'm totally with Guy Mancuso on that terrain.
They try to make robots that emulate the human, but they have failed so far in reproducing the walking properlly.
But it is fair to point that Nikon seems to do a better job in that area. I have zero experience with the D3, but from so many users I heard that the D3 AF hardly fails.
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Fred kind of my point was trust in the AF, not sure many folks really have it regardless of who makes it they can't think and I believe that makes many shooters nervous about AF taking control. As shooters we never want to ever lose that contol over a image. They are great to have onboard and sometimes a invaluable tool no question about it and sports almost everyone depends on it but trust is a big obstacle as well.
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I NEVER shot a advertising project with AF in all my 35 years, so I have to laugh a little because I know many shooters are the same as me stick it on manual and get to work. Sorry I just have never completely trusted any AF system on the planet and a very simple logical reason they can't think. They have no idea what is going on in your brain and what you are after. End of day though the modern MF bodies are much better than even a year ago but they can all be better as well.
And from an even older shooter, bingo!
Rob C
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To keep this on topic, about comparing these cameras . . . would some tester please, please, please, shoot something pretty with one of these things?
I've seen backyards, shoots of rainy streets from rooftops, alley's with blown out sky, shots of sunny streets from rooftops, (they all look like bad Homeland Security surveillance footage).
Jez . . . it seems every "tester" takes a gazillion dollar camera and shoots butt ugly photos. Come on shoot something real pretty, then explain from front to back the process, workflow and little things like did the firewire connection cut off, did the software crash, did the retoucher have to cut purple ca from around an image, did the camera jam, are there lenses available, can you shoot in low light, etc. etc. etc.
Then the forums light up with all the medium format players beating each other on the head saying there camera shows 4% better micro detail and can focus on a pimple from 9,000 ft. away.
And now to take this totally off topic . . . for Rob C. Not everyone in 'merica drives a V-8 they just wished they did, well except everyone that lives by the beach. On my block in Santa Monica there are 7 (yes 7) toyota Prius' (all black) and I live on a short block. 7:45 in the morning is funny cause all these cats come out and flick the remote to figure out which car is theirs. Consequently, If I drive 24 miles out of LA half the driveways have 5 liter V-8's in the driveway. 'merica really is two countries, the cities and the burbs and the burb folks have a lot of fun.
http://www.youtube.com/watch?v=St2FCxtlV7w (http://www.youtube.com/watch?v=St2FCxtlV7w)
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would some tester please, please, please, shoot something pretty with one of these things?
the latest trend is not to post any captures. Because monitors are not appropriate to judge about images
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..................Shhhh........................
To keep this on topic, about comparing these cameras . . . would some tester please, please, please, shoot something pretty with one of these things?
I've seen backyards, shoots of rainy streets from rooftops, alley's with blown out sky, shots of sunny streets from rooftops, (they all look like bad Homeland Security surveillance footage).
..................Shhhh.........................
And it seems a generalized reality all over the world.
I've checked 2 french websites about high-end gears and they do some testings.
The contents are really good until you reach the images. Although I saw some at least well done portraitures.
But it is the facade, the leaf, the tree, the garden, the fence, the dog and in the worst case the familly shots.
They could at least post a V8 engine.
This is the General Lee European version V8 dream
[attachment=22882:renault_...ine_a110.jpg]
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I am sure Mark will research the topic very carefully, and I do look forward to reading his coming article.
Edmund
Aaron,
Your aggressive tone is uncalled for. In fact since this was first raised by the Hasselblad rep and the issue came to our attention Mark has been aggressively pursuing as much technical information on the subject as he can, directly from senior engineering people at Leica and Phase One / Mamiya. Though in the past getting to high level technical contacts at Hasselblad has proven difficult, maybe now we can do so.
The net result is that when all the data is available and sorted out Mark now intends on writing something comprehensive on the subject, which I hope will benfit all of our understanding on the issue.
What I've learned so far is that while phase detection AF systems do not have "zones" the way that contrast detection systems do, they do indeed focus their lenses in discrete steps, and this is an understood issue in medium format AF design due to such systems' more shallow DOF than 35mm or smaller systems.
So I suggest that the name calling and finger pointing be shelved, and let's all wait to learn more about this subject. Mark Dubovoy is a scientist by profession, with a Phd in particle physics, and therefore well aware of the scientific method and how to apply it to researching and writing up a topic like this.
It appears that we all have something to learn on the subject.
Michael
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Still, what I'd love to see on any comparison is a test like the Zaguto people funded. Sure it may have some bias given Zaguto sells bits for dslrs, but overall when you fill the room of "working" professionals I doubt seriously if everyone there has any agenda other than to find out the facts.
http://www.zacuto.com/shootout (http://www.zacuto.com/shootout)
This was an interesting series, even though I have no plans to shoot HD video myself.
Did anybody notice that in the last episode they measured the DR of a 5D2 RAW as being 10.5-11 stops, using the "photographic" test that MF proponents argue for (backlit 13-stop glass step wedge). So much for the "6-7 stops for DSLR" argument.
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To keep this on topic, about comparing these cameras . . . would some tester please, please, please, shoot something pretty with one of these things?
I've seen backyards, shoots of rainy streets from rooftops, alley's with blown out sky, shots of sunny streets from rooftops, (they all look like bad Homeland Security surveillance footage).
Jez . . . it seems every "tester" takes a gazillion dollar camera and shoots butt ugly photos. Come on shoot something real pretty, then explain from front to back the process, workflow and little things like did the firewire connection cut off, did the software crash, did the retoucher have to cut purple ca from around an image, did the camera jam, are there lenses available, can you shoot in low light, etc. etc. etc.
Then the forums light up with all the medium format players beating each other on the head saying there camera shows 4% better micro detail and can focus on a pimple from 9,000 ft. away.
And now to take this totally off topic . . . for Rob C. Not everyone in 'merica drives a V-8 they just wished they did, well except everyone that lives by the beach. On my block in Santa Monica there are 7 (yes 7) toyota Prius' (all black) and I live on a short block. 7:45 in the morning is funny cause all these cats come out and flick the remote to figure out which car is theirs. Consequently, If I drive 24 miles out of LA half the driveways have 5 liter V-8's in the driveway. 'merica really is two countries, the cities and the burbs and the burb folks have a lot of fun.
http://www.youtube.com/watch?v=St2FCxtlV7w (http://www.youtube.com/watch?v=St2FCxtlV7w)
It's been done to a certain level http://forum.getdpi.com/forum/showthread.php?t=12243 (http://forum.getdpi.com/forum/showthread.php?t=12243) and raws to download which are still up. But I am not going to put great images up for raws to be used anywhere and YOU should know better than that. They are test files pure and simple but putting up real work is NOT something I will do especially the raws and no one testing these rigs will either and you know the reasons. The other side of this coin and I know I can speak for the rest of reviewers on this we are not getting one red nickel for our efforts either to even do these tests than take the heat because we really don't want to put up our real work of art. Sorry bud screw that I put something up really nice i want my pocket filled up really nice as well. From a guy that works for commerce I am surprised by your plea. This is a simple case and you especially can get anyone of these systems as a demo and run these test yourself and shoot all of the beautiful images you want.
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the latest trend is not to post any captures. Because monitors are not appropriate to judge about images
only prints 24x30 inch tell the IQ truth, according to recent LL sources.
peter
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Hi,
Yes I enjoyed the Zacuto tests. I'm somewhat confused about the contradictory statements on DR. My experience is that it is very well possible to extract a lot of shadow detail from my DSLRs (Sony), as a matter of fact, I was testing HDR but found that just using controls in LR (including liberal use of "fill light") I could achieve similar results from an "underexposed" picture. With HDR there was much less noise in the shadows, however.
I hope that some of the MF authors on LuLa will eventually elaborate the issue.
Best regards
Erik
This was an interesting series, even though I have no plans to shoot HD video myself.
Did anybody notice that in the last episode they measured the DR of a 5D2 RAW as being 10.5-11 stops, using the "photographic" test that MF proponents argue for (backlit 13-stop glass step wedge). So much for the "6-7 stops for DSLR" argument.
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Thanks for the link!
I have seen it before but it's time to revisit!
Best regards
Erik
It's been done to a certain level http://forum.getdpi.com/forum/showthread.php?t=12243 (http://forum.getdpi.com/forum/showthread.php?t=12243) and raws to download which are still up. But I am not going to put great images up for raws to be used anywhere and YOU should know better than that. They are test files pure and simple but putting up real work is NOT something I will do especially the raws and no one testing these rigs will either and you know the reasons. The other side of this coin and I know I can speak for the rest of reviewers on this we are not getting one red nickel for our efforts either to even do these tests than take the heat because we really don't want to put up our real work of art. Sorry bud screw that I put something up really nice i want my pocket filled up really nice as well. From a guy that works for commerce I am surprised by your plea. This is a simple case and you especially can get anyone of these systems as a demo and run these test yourself and shoot all of the beautiful images you want.
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It's been done to a certain level http://forum.getdpi.com/forum/showthread.php?t=12243 (http://forum.getdpi.com/forum/showthread.php?t=12243) and raws to download which are still up. But I am not going to put great images up for raws to be used anywhere and YOU should know better than that. They are test files pure and simple but putting up real work is NOT something I will do especially the raws and no one testing these rigs will either and you know the reasons. The other side of this coin and I know I can speak for the rest of reviewers on this we are not getting one red nickel for our efforts either to even do these tests than take the heat because we really don't want to put up our real work of art. Sorry bud screw that I put something up really nice i want my pocket filled up really nice as well. From a guy that works for commerce I am surprised by your plea. This is a simple case and you especially can get anyone of these systems as a demo and run these test yourself and shoot all of the beautiful images you want.
Cmon guy, that don't explain the rarity of brick wall raws
Edmund
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only prints 24x30 inch tell the IQ truth, according to recent LL sources.
exactly. obviously only at 300dpi - or 360dpi? - we can see the "real" resolution of lenses/chips. is that with "capture sharpening", "print sharpening", "creatve sharpening" or without any sharpening at all? And is it C-print or ink jet? which one on which paper?
As "the web is sRGB" ( ) only prints show the uncompressed gamut of the camera (nonsense, of course - no printer will show the entire gamut of a camera, not even a point and shoot camera. "...
Man, we all know how a 100% crop looks printed (in your preferred printing technique...). Too, who says that it is impossible to post small crops as 8bit TIF... if you really care about JPG compression (that is often not a problem at all... especially not in comparisions).
Etc. ...
Strange...
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Cmon guy, that don't explain the rarity of brick wall raws
Edmund
ROTFLMAO. Yea this is just a sun baked state . Brick walls last about a day here than burst into flames. LOL
Everyone please turn you AC units towards Arizona. Today it is cool at 106
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Fred
I well remember watching the Dukes series; it was a fascinating look into the imaginary life of the American boondocker. It also represented something almost aspirational - don't laugh - what with its CB radio etc. which, believe it or not, was banned in the UK for quite some time, as were the pirate radio stations, of which Radio Caroline (North and South) was my favourite. Many an otherwise lonely night in the darkroom was helped along by the Mamas and the Papas chanting about their 'darkest hour' being 'just before dawn'! Too bloody true! Another one that I loved, Radio Scotland, was local, and it was on when they announced that Elvis had left the building. Also, there was an ad for a modelling agency on it for a while, that I followed up and which led to my first contact with a pro version (as raw as myself at the time) of the genre from whence it all (my real photo life) began. So thanks, pirates.
But the Dooks' car: also a huge part of the US dream for other people. Living in India for some years I was quite used to the sight of US wheels of the 40s - early 50s; back in the UK (a song there?) maybe all folks saw of them was around USAF bases and compared with the junk that we produced in Britain and the prices of said rubbish when compared to the US home-buys, no wonder we thought the US a promised land. Somehow, that Ford Consul was never going to look cool with a Union Jack on the roof. The Mini graced some such motifs during the Carnaby Street era in the home-grown version of self-expression but it was something quaint rather than macho, art born of poverty.
I guess that America still remains a bit of a dream for non-Americans; we have been raised on the Hollywood version of reality and it was years before I, for one, accepted that not all Americans had V8s, swimming pools and lived in houses with white fences with a barn and a horse at the back. All cowboys played the guitar, had balls of steel that could withstand leaping down into a saddle from extraordinary hights (strong nags, too!) and, best of all, nobody ever had to work. Well, perhaps not best of all; best of all was that all the girls were fantastically beautiful, passed the days in school, cafés or flower shops, appeared to have no guile whatsoever and anyone could just walk up and stand a pretty good chance of scoring! The one bad thing: we all had to learn how to walk like Robert Mitchum. It was half-way easier for me, being called Robert, but that half was the only bit that worked.
I suspect that some large percentage of the US still quietly believes parts of the same dream: you'd have too - why else continue the battle against the odds? For the rest of us - maybe disillusion sets in earlier, not a happier choice. Obviously enough.
But without dreams we might as well emulate the lemming.
Rob C
Yes it's true. US girls are easy.
Steve Hendrix
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... I am not going to put great images up for raws to be used anywhere and YOU should know better than that. They are test files pure and simple but putting up real work is NOT something I will do especially the raws and no one testing these rigs will either and you know the reasons.
I agree and furthermore I'll never test any equipment on important shoots because optimal or not I have to have the camera ingrained in my soul when the photons meet the silicon otherwise I'm going to screw something up. For testing equipment I'll use repeatable boring subjects where a screwup isn't a big deal.
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Let me focus (pun intended) on a single sentence in David's post:
"The stepper motors in the H lenses do not suffer from this issue".
Therefore, according to David, Hasselblad uses stepper motors to focus their lenses.
The definition of a stepper motor is as follows: A stepper motor is a special type of electric motor that moves in increments, or steps, rather than turning smoothly as a conventional motor does.
Therefore, the Hasselblad lenses focus in steps.
I rest my case.
Ok, I have found myself with a bit of airport time so will respond to Mark and Michael in one post.
From Mark...
My understanding from the technical papers and my direct conversations with at least one MF manufacturer is that the issue is not measuring distances with a phase detection system. You are correct that this can be done continuously. The issue is the mechanics of the lens itself. You need quite a bit of torque to get the focusing system to start moving. The system has inertia, as well as gears and other moving parts. There is a limit as to how "continuous" these parts can move. There is also a limit as to how fast you can apply the brakes and stop the movement. When you put all that together, the mechanisms themselves are not continuous and cannot be moved in infinitesimally small increments. They are "jumpy" and they focus in discrete steps or zones.
I expect the manufacturer you are talking about does not use motors inside the lens to drive the focussing optics but rather a motor inside the camera body? Hasselblad uses motors inside the lens, so a larger lens can use a larger motor etc etc.
The advantage of the motor inside the lens is that there is no mechanical connection needed to be made when attaching the lens to the camera body. The small armature that protrudes from the lens mount to drive the mechanics I would expect to have some degree of mechanical slop, albeit a small amount.
Therefore as you get to the far range of focus and smaller amounts of movement on the optics need to be applied then the mechanical intolerance (if thats a word) would render it difficult to make precise steps and therefore have a jumpy effect with the result be a loss in finite focussing. So I assume this is the conclusion from your conversations with Mamiya? Please correct me if I am wrong.
The stepper motors in the H lenses do not suffer from this issue. If you connect an H camera to our Phocus software you can see this yourself. Using the camera control tool, you can manipulate the focus using the + and - buttons. Hold down the Cmd key whilst clicking these buttons and this will give you an extremely fine focus. ie they can be moved in infinitesimally small increments.
I hope that clears it up from my end.
If you wanted to research further, what you could investigate is when the AF drive goes back at forth at some point the camera will decide “Im in focus within my factory set tolerance”. I cannot find any data from Canon and Nikon which describes this tolerance. Perhaps it is mentioned in the Leica articles?
The tolerance for us does not change at either end of the focussing scale.
From Michael...
What I've learned so far is that while phase detection AF systems do not have "zones" the way that contrast detection systems do, they do indeed focus their lenses in discrete steps, and this is an understood issue in medium format AF design due to such systems' more shallow DOF than 35mm or smaller systems.
I hope with my words above I have tried to describe that this is not the case with the Hasselblad AF system.
From my work eons ago as a motorsport photographer (Using Manual Focus!! Ugh!!) I would expect a Nikon / Canon 400mm/500mm+ does not have very much DOF at the infinity scale. Perhaps it is interesting to know from our readers if they feel the 35mm systems fail at infinity focussing?
To close, I am sorry to hear if you felt that it was hard to get in touch with someone at Hasselblad. However, I have been a pretty active poster here for a couple of years and am only a PM away.
Best Regards,
David
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Folks:
The time has come to put final closure to all the arguments and speculation about autofocus systems.
I have spent the last few days in contact with all the relevant top level technical personnel at PhaseOne and Leica. To make sure you all understand this, I have been in contact with the people that actually designed the current autofocus systems, with the people that manufacture them, with the Technical Directors in charge of the product lines and with the Chief Technical Officers. This is what I call "the horse's mouth".
In my conversations with these companies, they have verified that the statements in my article are factually and technically correct:
- Autofocus systems work in small steps and not continuously.
- They have verified that my prior posts on this forum are technically correct.
- Finally, they have also verified that distant objects are the most likely to cause autofocus failures. As mentioned in my article, this is exactly what I have observed in the field, and the explanation given in my prior post about this is technically correct.
The Technical Director in charge of the S2 at Leica put it most eloquently. I am always sensitive about not disclosing information that might be considered confidential by a company, so I apologize to the curious members of the forum who would like to know the exact numbers. I will leave it up to Leica as to whether they wish to publicly disclose those numbers.
Here is the quote:
"Reliability is not only one of the major features of the complete S-system but is also a very important point with respect to AF operation. That the S2 AF performance (reliability, speed and precision) is so high has many reasons. It is an advantage to have very small focus steps at distances approaching infinity (where you have the least depth of field), and where the lens has to focus very precisely. The Leica Summarit-S 70mm has a focus resolution of ___ micron (=1 focus step). Furthermore there is a f-stop correction depending on the focus distance. The operating temperature, which also has a big impact on AF precision, is considered as well. But most important is that all lenses and cameras are checked very carefully (and if necessary corrected) by our QA department before they are delivered to our customers. The AF and image sensor planes (CCD) are aligned most precisely. These smallest tolerances are only possible with an integrated digital system! "
To summarize:
While I knew at the time that I wrote the article that all the information in it was thoroughly researched, and factually and technically correct, having done the exercise a second time with the folks mentioned above, I once again stand 100% behind everything written in my article about the S2
Best regards and good luck to all.
Mark Dubovoy
Ok, I have found myself with a bit of airport time so will respond to Mark and Michael in one post.
From Mark...
My understanding from the technical papers and my direct conversations with at least one MF manufacturer is that the issue is not measuring distances with a phase detection system. You are correct that this can be done continuously. The issue is the mechanics of the lens itself. You need quite a bit of torque to get the focusing system to start moving. The system has inertia, as well as gears and other moving parts. There is a limit as to how "continuous" these parts can move. There is also a limit as to how fast you can apply the brakes and stop the movement. When you put all that together, the mechanisms themselves are not continuous and cannot be moved in infinitesimally small increments. They are "jumpy" and they focus in discrete steps or zones.
I expect the manufacturer you are talking about does not use motors inside the lens to drive the focussing optics but rather a motor inside the camera body? Hasselblad uses motors inside the lens, so a larger lens can use a larger motor etc etc.
The advantage of the motor inside the lens is that there is no mechanical connection needed to be made when attaching the lens to the camera body. The small armature that protrudes from the lens mount to drive the mechanics I would expect to have some degree of mechanical slop, albeit a small amount.
Therefore as you get to the far range of focus and smaller amounts of movement on the optics need to be applied then the mechanical intolerance (if thats a word) would render it difficult to make precise steps and therefore have a jumpy effect with the result be a loss in finite focussing. So I assume this is the conclusion from your conversations with Mamiya? Please correct me if I am wrong.
The stepper motors in the H lenses do not suffer from this issue. If you connect an H camera to our Phocus software you can see this yourself. Using the camera control tool, you can manipulate the focus using the + and - buttons. Hold down the Cmd key whilst clicking these buttons and this will give you an extremely fine focus. ie they can be moved in infinitesimally small increments.
I hope that clears it up from my end.
If you wanted to research further, what you could investigate is when the AF drive goes back at forth at some point the camera will decide “Im in focus within my factory set tolerance”. I cannot find any data from Canon and Nikon which describes this tolerance. Perhaps it is mentioned in the Leica articles?
The tolerance for us does not change at either end of the focussing scale.
From Michael...
What I've learned so far is that while phase detection AF systems do not have "zones" the way that contrast detection systems do, they do indeed focus their lenses in discrete steps, and this is an understood issue in medium format AF design due to such systems' more shallow DOF than 35mm or smaller systems.
I hope with my words above I have tried to describe that this is not the case with the Hasselblad AF system.
From my work eons ago as a motorsport photographer (Using Manual Focus!! Ugh!!) I would expect a Nikon / Canon 400mm/500mm+ does not have very much DOF at the infinity scale. Perhaps it is interesting to know from our readers if they feel the 35mm systems fail at infinity focussing?
To close, I am sorry to hear if you felt that it was hard to get in touch with someone at Hasselblad. However, I have been a pretty active poster here for a couple of years and am only a PM away.
Best Regards,
David
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Here is the quote:
"Reliability is not only one of the major features of the complete S-system but is also a very important point with respect to AF operation. That the S2 AF performance (reliability, speed and precision) is so high has many reasons. It is an advantage to have very small focus steps at distances approaching infinity (where you have the least depth of field), and where the lens has to focus very precisely. Mark Dubovoy
Isn't there something a little skewed about this statement?
Rob C
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So who is right now and who's not?
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Folks:
The time has come to put final closure to all the arguments and speculation about autofocus systems.
I have spent the last few days in contact with all the relevant top level technical personnel at PhaseOne and Leica. To make sure you all understand this, I have been in contact with the people that actually designed the current autofocus systems, with the people that manufacture them, with the Technical Directors in charge of the product lines and with the Chief Technical Officers. This is what I call "the horse's mouth".
In my conversations with these companies, they have verified that the statements in my article are factually and technically correct:
- Autofocus systems work in small steps and not continuously.
- They have verified that my prior posts on this forum are technically correct.
- Finally, they have also verified that distant objects are the most likely to cause autofocus failures. As mentioned in my article, this is exactly what I have observed in the field, and the explanation given in my prior post about this is technically correct.
The Technical Director in charge of the S2 at Leica put it most eloquently. I am always sensitive about not disclosing information that might be considered confidential by a company, so I apologize to the curious members of the forum who would like to know the exact numbers. I will leave it up to Leica as to whether they wish to publicly disclose those numbers.
Here is the quote:
"Reliability is not only one of the major features of the complete S-system but is also a very important point with respect to AF operation. That the S2 AF performance (reliability, speed and precision) is so high has many reasons. It is an advantage to have very small focus steps at distances approaching infinity (where you have the least depth of field), and where the lens has to focus very precisely. The Leica Summarit-S 70mm has a focus resolution of ___ micron (=1 focus step). Furthermore there is a f-stop correction depending on the focus distance. The operating temperature, which also has a big impact on AF precision, is considered as well. But most important is that all lenses and cameras are checked very carefully (and if necessary corrected) by our QA department before they are delivered to our customers. The AF and image sensor planes (CCD) are aligned most precisely. These smallest tolerances are only possible with an integrated digital system! "
To summarize:
While I knew at the time that I wrote the article that all the information in it was thoroughly researched, and factually and technically correct, having done the exercise a second time with the folks mentioned above, I once again stand 100% behind everything written in my article about the S2
Best regards and good luck to all.
Mark Dubovoy
1) Refreshing! it results that when the information is asked at the right sources we may once for a while give up the forum erasmus scientist speculations, but I'm afraid it won't happen anyway and "good" (and scientific of course) arguments against will fall very soon on the battle field. Ok, at least another perspective has emerged.
And I would like to have some confirmations from the same sources about that DR stuff that always puts the forum into flammes, when everybody see 1 stop or when I see 4 in practise. As I'm human, I'd like to know where I'm failing or if this just 1 stop is just a collective illusion...
Anyway, maybe before asking for the Mark's head like in the French revolution we should think if we are really capable of managing the right information.(and I'm including myself here)
There is a lot of lecture over the internet.
2) About the print/web. This is simply ridiculous IMO.
If you can't judge images on the web I doubt you'll be able to on a print, regardless on the differences in bits and resolution.
3) ............About the last BCooter post............
This one was psychadelic.
If there is one person on this forum who can have access to the gear and test in real field and produce top images with it is BCooter.I can't beleive that one of the world's most influent commercial photographer does not have the right key to open these doors.
Or he does not have the time because of his agenda to do the testings to his standards, or he likes teasing.
I always find the BC posts very informatives and frankly "above the crowd", except when he comes over and over again on how bad are those testings.
I join the Guy's Mancuso post here on that matter.
Don't get me wrong, BC is right in essence. I'm also fed up to see the happy familly kind of pictures that are generally spread over the internet in gear testing.
And it is true that very little if no information is deliver regarding the PP, the tech issues, the tether task etc...
But the problem is exactly what you see here: Even if people would do those testing in BC's minimum standards, they are poorly rewarded.
Immediatly the "expert's forums" will jump agressivly on the scenery with any arguments against the lightning, that this or that mistake was done with the software,
that the writter has done a big semantic error, that they did not tether with the right cable, that the computer was not maintained properlly, that he should have use this other lens that focus faster,
etc...and in the best cases with manners but generally agressive and cynical reactions.
that anyway we can't judge the pics over internet etc...
So you have all the moderators suddenly busy, and I imagine they will like to use their time better, in order to keep the forum elegance and manners. No surprise if people who could do the testing
in the most professional way say no thanks.
If Raw files where deliver it would just be the same story.
So, even if someone was tempted to do those testings in a real pro environment it would generally not happen because of those reasons.
Zacuto have done some good stuff because their structure allow them to do so and there is a commercial reason behind also.
Remember the James Russell article on the Leica M9 and the reactions? Completly crazy.
Remember the reactions when Michael said that famous word about the K7 calling it just "competent"? I was absolutly amazed by the forum's reactions.(and I also shoot Pentax and
I saw the same things as Michael saw in his article and did not feel offended because a brand I own does not convince...Pentaxes forums where all in flammes after that, simply hilarious)
etc...
The problem with photography, is that there is a quasi mystic and sexual connection between gear and user. That is why we never see women in those kind of battlefields.
Brands are like the football team we supports so obviously there is an against necessity. It is competition and who's got the biggest one.
This is the tennage age. The differences between women and men, is that in men the teenage age lasts much longuer...
But yes, American girls are easy.
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Yes it's true. US girls are easy.
Steve Hendrix
I have reliable sources who tell me they're easy - as long as you're not yet married to them
Edmund
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Let me focus (pun intended) on a single sentence in David's post:
"The stepper motors in the H lenses do not suffer from this issue".
Therefore, according to David, Hasselblad uses stepper motors to focus their lenses.
The definition of a stepper motor is as follows: A stepper motor is a special type of electric motor that moves in increments, or steps, rather than turning smoothly as a conventional motor does.
Therefore, the Hasselblad lenses focus in steps.
I rest my case.
Mark,
EDIT - I apologise but I have made an error. The Aperture drive uses a stepper motor for precise setting of aperture increments. The focus drive uses a DC motor. I had got them mixed up in my old age.
So we can set any distance as described earlier. Information relayed to me from the product manager.
Apologies to all!
The DC motor in the lens is finite enough for us to be able to set any distance as I stated earlier. Again, connect an H2/3/4D to Phocus, hit the remote focussing button with the Cmd key applied and you will see exactly how small one click is.
The Leica specialist's quote is 100% correct...
"Reliability is not only one of the major features of the complete S-system but is also a very important point with respect to AF operation. That the S2 AF performance (reliability, speed and precision) is so high has many reasons. It is an advantage to have very small focus steps at distances approaching infinity (where you have the least depth of field), and where the lens has to focus very precisely. The Leica Summarit-S 70mm has a focus resolution of ___ micron (=1 focus step). Furthermore there is a f-stop correction depending on the focus distance. The operating temperature, which also has a big impact on AF precision, is considered as well. But most important is that all lenses and cameras are checked very carefully (and if necessary corrected) by our QA department before they are delivered to our customers. The AF and image sensor planes (CCD) are aligned most precisely. These smallest tolerances are only possible with an integrated digital system! "
Of course they don't reveal what the focus resolution is and I wouldn't expect them too. Nor do we. ;-)
Also note he/she says "It is an advantage to have very small focus steps". Not "Leica has smaller focus steps than anyone else!". So they are being very honest about their AF description which is nice.
So we can summarise...
1) Small Focus steps at infinity are an advantage
2) Aperture dependant focus correction is an advantage
3) Lenses / Cameras are calibrated for AF accuracy as part of an integrated system
Its nice to see we operate in exactly the same way as Leica.
The only way to differentiate certain systems is the value/tolerance at which the camera decides it is in focus. These figures, not available. The other way is....
At the end of the day the maths is meaningless if a Photographer picks up a camera and says the Hasselblad/Phase/Leica AF sucks/excels in certain conditions. Period. If you feel the Leica responded better than other cameras you have used, then I value this opinion more than the science behind it.
I'm sorry Mark, but I still think the wording in your original article is misleading. You also contradict yourself by saying the lenses have "essentially no focus shift" when the Leica specialist says otherwise.
Best Regards,
David
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I have reliable sources who tell me they're easy - as long as you're not yet married to them
Edmund
they stay easy - even after marriage ...?
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snip
Don't get me wrong, BC is right in essence. I'm also fed up to see the happy familly kind of pictures that are generally spread over the internet in gear testing.
And it is true that very little if no information is deliver regarding the PP, the tech issues, the tether task etc...
But the problem is exactly what you see here: Even if people would do those testing in BC's minimum standards, they are poorly rewarded.
Am I teasing. Well sort of, but hey it's a tough job and somebody's got to do it.
Am I serious about seeing better testing photographs, yes, definitely because nothing is a buzz kill when reading about a $50,000 camera system than seeing shots off a roof on a rainy day.
I dig photographs much more than cameras, I like looking at pretty photographs, strange photographs, exceptional photographs and daring photographs. That's why we buy these things.
Mark and Guy are probably correct that they're not paid for testing and writing and I don't know the financial aspects of LL or Guy's site, but there has to be more reasons for doing it than just seeing your name in print.
But, don't get me wrong, I liked the article and understand what it is like to be on the sharp point of a stick. J.R. wrote sumtin' about first time focusing with a range finder and caught a load a c#$p over it, but also received some of the nicest comments about the article he ever received. (At least that's what he told me). insert one of those silly smiley faces here.
But J.R. took the Leica out of the box and shot an editorial spread with it. Not completely and there were other cameras used and a whole bunch of backups, but it was put into a professional setting and I (uh excuse me J.R.) learned bunches from that experience.
So if there is a reason I post, other than to give myself a break from rendering video, doing an estimate to version 5 or negotiating reuse for the 12th time, it's to try to make the point that these cameras are made to take pretty photographs, not color charts.
You could hand that Leica off to my friends gwitif, or rogan, or a whole bunch of photographers I know that could really put it through it's paces and turn something that would be noteworthy. (I'm not saying Mark can't either, so don't read me wrong).
Now the downside to this is if rogan finds it takes 3 hours for the previews to pop up when tethering, or gwitif sees purple ca on any backlit object, they're gonna say it, cause that's the kind of people they are, but then again that's what should be reported the good and the need to be fixed bad.
Anyway, I would think it would be in the camera makers best interest to try this route.
IMO
P.S.
In regards to focus, it's all subject dependent, but I can promise you no large body of work is ever shot without some missed focus, at least with mechanical cameras, maybe Pixtar doesn't have those issues, but we do.
Best,
BC
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It is an advantage to have very small focus steps at distances approaching infinity (where you have the least depth of field), and where the lens has to focus very precisely.
Isn't there something a little skewed about this statement?
Yes!
Perhaps he intended to say that a small step in the focus motor results in a large difference in subject focus distance. However, at the same time DOF is relatively huge in absolute terms when focussing near infinity. What's more, a sensor array with sensels of finite dimensions has a hard maximum resolution limit, and thus resulting DOF. The combination of a little diffraction wide open and sensel surface area will make it impossible to discriminate between focus positions within a certain 'DOF zone', which happens to be huge near infinity.
Cheers,
Bart
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David,
All of this leads me to ask YOU directly a question which has always puzzled me:
How does Hasselblad ensure that the MANUAL focus is accurate?
I would appreciate an informative answer or else a refusal to answer, but no Leicaish boilerplate.
Edmund
Mark,
EDIT - I apologise but I have made an error. The Aperture drive uses a stepper motor for precise setting of aperture increments. The focus drive uses a DC motor. I had got them mixed up in my old age.
So we can set any distance as described earlier. Information relayed to me from the product manager.
Apologies to all!
The DC motor in the lens is finite enough for us to be able to set any distance as I stated earlier. Again, connect an H2/3/4D to Phocus, hit the remote focussing button with the Cmd key applied and you will see exactly how small one click is.
The Leica specialist's quote is 100% correct...
"Reliability is not only one of the major features of the complete S-system but is also a very important point with respect to AF operation. That the S2 AF performance (reliability, speed and precision) is so high has many reasons. It is an advantage to have very small focus steps at distances approaching infinity (where you have the least depth of field), and where the lens has to focus very precisely. The Leica Summarit-S 70mm has a focus resolution of ___ micron (=1 focus step). Furthermore there is a f-stop correction depending on the focus distance. The operating temperature, which also has a big impact on AF precision, is considered as well. But most important is that all lenses and cameras are checked very carefully (and if necessary corrected) by our QA department before they are delivered to our customers. The AF and image sensor planes (CCD) are aligned most precisely. These smallest tolerances are only possible with an integrated digital system! "
Of course they don't reveal what the focus resolution is and I wouldn't expect them too. Nor do we. ;-)
Also note he/she says "It is an advantage to have very small focus steps". Not "Leica has smaller focus steps than anyone else!". So they are being very honest about their AF description which is nice.
So we can summarise...
1) Small Focus steps at infinity are an advantage
2) Aperture dependant focus correction is an advantage
3) Lenses / Cameras are calibrated for AF accuracy as part of an integrated system
Its nice to see we operate in exactly the same way as Leica.
The only way to differentiate certain systems is the value/tolerance at which the camera decides it is in focus. These figures, not available. The other way is....
At the end of the day the maths is meaningless if a Photographer picks up a camera and says the Hasselblad/Phase/Leica AF sucks/excels in certain conditions. Period. If you feel the Leica responded better than other cameras you have used, then I value this opinion more than the science behind it.
I'm sorry Mark, but I still think the wording in your original article is misleading. You also contradict yourself by saying the lenses have "essentially no focus shift" when the Leica specialist says otherwise.
Best Regards,
David
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David,
All of this leads me to ask YOU directly a question which has always puzzled me:
How does Hasselblad ensure that the MANUAL focus is accurate?
I would appreciate an informative answer or else a refusal to answer, but no Leicaish boilerplate.
Edmund
I refuse! ;-)
Well, I guess we can't ensure manual focus is accurate. If you use the focus indicator lights in the viewfinder this is using the Phase Detection hardware to 'tell' you when the subject in the crosshairs is in focus.
Aperture dependant focus corrections are not made when in MF mode as I would imagine most photographers would be quite upset if the camera starting shifting the lens if you had purposely disabled it.
Perhaps though some functionality of being able to indicate an aperture focus correction could be useful. But I would imagine most customers would prefer we don't interfere, if the camera is set to manual.
David
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I refuse! ;-)
Well, I guess we can't ensure manual focus is accurate. If you use the focus indicator lights in the viewfinder this is using the Phase Detection hardware to 'tell' you when the subject in the crosshairs is in focus.
Aperture dependant focus corrections are not made when in MF mode as I would imagine most photographers would be quite upset if the camera starting shifting the lens if you had purposely disabled it.
Perhaps though some functionality of being able to indicate an aperture focus correction could be useful. But I would imagine most customers would prefer we don't interfere, if the camera is set to manual.
David
and while we know about the careful check of the lens-sensor distance, and the check of the lens-AF sensor distance, what about a check of the optical path to the viewfinder?
shall we assume that precise MF is simply unsupported?
Edmund
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Am I teasing. Well sort of, but hey it's a tough job and somebody's got to do it.
Am I serious about seeing better testing photographs, yes, definitely because nothing is a buzz kill when reading about a $50,000 camera system than seeing shots off a roof on a rainy day.
I dig photographs much more than cameras, I like looking at pretty photographs, strange photographs, exceptional photographs and daring photographs. That's why we buy these things.
Mark and Guy are probably correct that they're not paid for testing and writing and I don't know the financial aspects of LL or Guy's site, but there has to be more reasons for doing it than just seeing your name in print.
But, don't get me wrong, I liked the article and understand what it is like to be on the sharp point of a stick. J.R. wrote sumtin' about first time focusing with a range finder and caught a load a c#$p over it, but also received some of the nicest comments about the article he ever received. (At least that's what he told me). insert one of those silly smiley faces here.
But J.R. took the Leica out of the box and shot an editorial spread with it. Not completely and there were other cameras used and a whole bunch of backups, but it was put into a professional setting and I (uh excuse me J.R.) learned bunches from that experience.
So if there is a reason I post, other than to give myself a break from rendering video, doing an estimate to version 5 or negotiating reuse for the 12th time, it's to try to make the point that these cameras are made to take pretty photographs, not color charts.
You could hand that Leica off to my friends gwitif, or rogan, or a whole bunch of photographers I know that could really put it through it's paces and turn something that would be noteworthy. (I'm not saying Mark can't either, so don't read me wrong).
Now the downside to this is if rogan finds it takes 3 hours for the previews to pop up when tethering, or gwitif sees purple ca on any backlit object, they're gonna say it, cause that's the kind of people they are, but then again that's what should be reported the good and the need to be fixed bad.
Anyway, I would think it would be in the camera makers best interest to try this route.
IMO
P.S.
In regards to focus, it's all subject dependent, but I can promise you no large body of work is ever shot without some missed focus, at least with mechanical cameras, maybe Pixtar doesn't have those issues, but we do.
Best,
BC
Alright tethered . The S2 sucks and i did not even bother after reading Michael mentioning it took forever to get a preview. With paid models on my set it was not worth the time to even bother. I admit it was not my focus of attention. P40+ is a whole different kettle of fish. I have said several time 2 second preview , has never crashed even going very fast as the strobes will allow and sensor plus is even faster. Yes you can turn camera off and on and not lose the tethering or rebooting of program and pulling cord I was able to immediately connect again. My only problem I have had and I think it is more my computer or the firewire cable itself is on initial plugin of firewire cable the software is not seeing the connection without a restart. That is not a software issue or C1 in this case but my belief a faulty Firewire 800 cable and that is something I want to sort out.
Now every reviewer also wants to get out and shoot so not every aspect of a cam is covered. Some technical things where discussed in other reports and given the time we have than some of us leave certain things out so we can get to other area's that we feel important. Yes Jack and I are for sure guilty of that , our goal was to shoot in some varied settings that have not been done. Models for one in the brightest light around here in Arizona was a big one for me that we wanted to see how these cams can handle that type of light range and only did some stuff with lighting because others where doing that. Admittedly we where cherry picking for different situations to show what range these cams had and did not shoot somethings as others have. Given the time we had it was our best call. I am sure others also did this as well to fit there work and desire to test different things.
Now I don't know about anyone else but our forum makes no money from anything except workshops themselves. No banner ads and such and we have enjoyed that advertising free setting and more importantly we do these out of the love of photography and also to help our readers understand these systems better. Frankly we owe nothing to anyone and no one pays us for that data. Call us all good guys willing to help others if you will but sure in the end we hope people will come to a workshop and learn more. I can't sit here and say differently and won't. I freely admit GM Photography is for commerce and GetDPI is my love. Anyone want to throw rocks at that go right ahead but the folks you have mentioned can get demo's of this gear anytime you want and if not let me know and I can help arrange those demo's if your serious about a future purchase, I'm not going to waste people's time on that just for curiosity sake. There are dealers here and our place that can certainly help people send them a PM and they will help, in the end they are all really nice folks and I have met a lot of them. Now I am not going to defend any review I do as it is what it is and I provide the raws for folks to test the files themselves all free and everyones reviews are all free. Like Fred said we are not crazy about the rocks thrown but are willing to still do these in spite of it and that I know I can speak for everyone that does them. Name in print is meaningless so let's not go there, end of day we love photography plain and simple. After 35 years it's my whole life I better freaking love it just like a marriage or we are in trouble . Now honestly a lot of images may not be pretty but you can gain information from them and really that all that counts. If you can't get what you want from them than do a demo but please don't ever say to me you are too busy, so am I and we have families to care for as well and also our commerce daily routine.
My last comment and I think I can speak for the folks that do these reviews is we try to do the best we can and we will make mistakes along the way no doubt we are only human but at least we are doing them and trying to help others. If not than we are back to the old days with no data and you put down your 50 k and than suck air because it is not what your really wanted because no data was around to help you. You can love us , hate us but end of day you need us. End of my early morning comments and off to more espresso.
Pardon the typos if any not looking back to fix them. Off for another round of chemo for my wife
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and while we know about the careful check of the lens-sensor distance, and the check of the lens-AF sensor distance, what about a check of the optical path to the viewfinder?
shall we assume that precise MF is simply unsupported?
Edmund
No.
Mirror is also adjusted to the focussing screen on a per camera basis.
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No.
Mirror is also adjusted to the focussing screen on a per camera basis.
Isn't it incredible? That would have been the very first thing that I would have taken for granted with absolutely any reflex camera! Please don't tell me that because of the af and now digital age you are unique in checking these things out - please?
Rob C
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Here is the quote:
"Reliability is not only one of the major features of the complete S-system but is also a very important point with respect to AF operation. That the S2 AF performance (reliability, speed and precision) is so high has many reasons. It is an advantage to have very small focus steps at distances approaching infinity (where you have the least depth of field), and where the lens has to focus very precisely. The Leica Summarit-S 70mm has a focus resolution of ___ micron (=1 focus step). Furthermore there is a f-stop correction depending on the focus distance. The operating temperature, which also has a big impact on AF precision, is considered as well. But most important is that all lenses and cameras are checked very carefully (and if necessary corrected) by our QA department before they are delivered to our customers. The AF and image sensor planes (CCD) are aligned most precisely. These smallest tolerances are only possible with an integrated digital system! "
Mark Dubovoy
Mark,
I enjoyed your article and accepted your observation that autofocus of the S2 was very accurate. While the theory (steps vs continuous focusing) is interesting, the observation is not affected by the theory. I am surprised that your German expert states that the depth of field is least at subject distances approaching infinity. I think he should have used depth of focus (http://en.wikipedia.org/wiki/Depth_of_focus), not depth of field. Depth of focus can be calculated: t = 1*N*c*(v/f), where t is the depth of focus, N the f/number, v the image distance, and f is the lens focal length. With a subject distance of infinity, v = f and t is at its minimum. With less subject distances, you have to rack out the lens, increasing v and thus the depth of focus (t). As all photographers know, depth of field is less with closeups.
That the smallest tolerances are possible only with integrated systems are borne out by Joseph Holmes experiences with various MFDBs (cited above).
Because of focus shift when stopping down and imprecision in AF sensor and image planes, the best focus with dSLRs is obtained with live view. Does the S2 have this?
Regards,
Bill
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Because of focus shift when stopping down and imprecision in AF sensor and image planes, the best focus with dSLRs is obtained with live view. Does the S2 have this?
Who would have thought even 3 years ago that the ability to generate a live stream from a sensor would get on the critical path of image quality?
That single shortcoming though is the main reason why I am not seriously considering buying a Pentax 645D. The good news being that I might devote the cash on something real useful instead... like a new pair of speakers?
Cheers,
Bernard
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they stay easy - even after marriage ...?
Can we talk about the discrete nature of autofocus please?
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Congratulations Bernard & wish you many joys outside of our L-L bubble.
Thks Sean, it would indeed seem that this a life outside.
Cheers,
Bernard
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Isn't it incredible? That would have been the very first thing that I would have taken for granted with absolutely any reflex camera! Please don't tell me that because of the af and now digital age you are unique in checking these things out - please?
Rob C
I would imagine this is common practice.
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Isn't it incredible? That would have been the very first thing that I would have taken for granted with absolutely any reflex camera! Please don't tell me that because of the af and now digital age you are unique in checking these things out - please?
Rob C
It's not something you should take for granted with reflex cameras near the lower end of the price scale.
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It's not something you should take for granted with reflex cameras near the lower end of the price scale.
And then there is wear and tear in the field. Bounce a mirror 50K times ....
Edmund
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I am surprised that your German expert states that the depth of field is least at subject distances approaching infinity. I think he should have used depth of focus (http://en.wikipedia.org/wiki/Depth_of_focus), not depth of field.
Hi Bill,
That sounds like a plausible explanation, because the statement as originally made didn't make sense.
Too bad the quoteThe Leica Summarit-S 70mm has a focus resolution of ___ micron (=1 focus step).
lost it's crucial bit of information, the number of microns focus resolution. If small enough it wouldn't matter whether a stepper motor was used or a DC motor.
Cheers,
Bart
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Sorry David, but it is you who is incorrect again.
There is nothing in the "Leica specialist" (as you call him) part of the quote that I shared with the group regarding focus shift. You might be confused with the wording about an F/stop correction, which is something completely different.
In fact, the more complete quote is as follows:
"The prerequisite for the highest image quality is represented by the S-lenses – the key competence of Leica. Let’s have a look at the MTF curves (available on the Leica S Microsite). I think the facts speak for themselves. Highest optical performance is provided at full stop, from the close-up limit to infinity. There is no focus-shift while stopping down due to flowting lens elements. Additionally the use of the best available types of glass and aspherical / apochromatical designs minimize optical abberations. There is no need for time and money wasting software corrections.
Reliability is not only one of the major features of the complete S-system but is also a very important point with respect to AF operation. That the S2 AF performance (reliability, speed and precision) is so high has many reasons. It is an advantage to have very small focus steps at distances approaching infinity (where you have the least depth of field), and where the lens has to focus very precisely. The Leica Summarit-S 70mm has a focus resolution of ___ micron (=1 focus step). Furthermore there is a f-stop correction depending on the focus distance."
And goes on from there.
Please pay attention to the sentence "there is no focus shift while stopping down...." (sorry, he is German and misspelled the word "floating"). Read it again. He does not say "minima"l or "small" focus shift; he says "no focus shift". Coming from a company as conservative as Leica, this is quite a strong statement.
I have a slight suspicion that you did not like my article. ..
:-)
However, as I said before, I stand 100% behind everything I said in the article. All the information is factually and technically correct.
I have nothing else to say, and therefore, this is my last post on this thread.
Best regards,
Mark
Mark,
EDIT - I apologise but I have made an error. The Aperture drive uses a stepper motor for precise setting of aperture increments. The focus drive uses a DC motor. I had got them mixed up in my old age.
So we can set any distance as described earlier. Information relayed to me from the product manager.
Apologies to all!
The DC motor in the lens is finite enough for us to be able to set any distance as I stated earlier. Again, connect an H2/3/4D to Phocus, hit the remote focussing button with the Cmd key applied and you will see exactly how small one click is.
The Leica specialist's quote is 100% correct...
"Reliability is not only one of the major features of the complete S-system but is also a very important point with respect to AF operation. That the S2 AF performance (reliability, speed and precision) is so high has many reasons. It is an advantage to have very small focus steps at distances approaching infinity (where you have the least depth of field), and where the lens has to focus very precisely. The Leica Summarit-S 70mm has a focus resolution of ___ micron (=1 focus step). Furthermore there is a f-stop correction depending on the focus distance. The operating temperature, which also has a big impact on AF precision, is considered as well. But most important is that all lenses and cameras are checked very carefully (and if necessary corrected) by our QA department before they are delivered to our customers. The AF and image sensor planes (CCD) are aligned most precisely. These smallest tolerances are only possible with an integrated digital system! "
Of course they don't reveal what the focus resolution is and I wouldn't expect them too. Nor do we. ;-)
Also note he/she says "It is an advantage to have very small focus steps". Not "Leica has smaller focus steps than anyone else!". So they are being very honest about their AF description which is nice.
So we can summarise...
1) Small Focus steps at infinity are an advantage
2) Aperture dependant focus correction is an advantage
3) Lenses / Cameras are calibrated for AF accuracy as part of an integrated system
Its nice to see we operate in exactly the same way as Leica.
The only way to differentiate certain systems is the value/tolerance at which the camera decides it is in focus. These figures, not available. The other way is....
At the end of the day the maths is meaningless if a Photographer picks up a camera and says the Hasselblad/Phase/Leica AF sucks/excels in certain conditions. Period. If you feel the Leica responded better than other cameras you have used, then I value this opinion more than the science behind it.
I'm sorry Mark, but I still think the wording in your original article is misleading. You also contradict yourself by saying the lenses have "essentially no focus shift" when the Leica specialist says otherwise.
Best Regards,
David
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I have a slight suspicion that you did not like my article. ..
:-)
However, as I said before, I stand 100% behind everything I said in the article. All the information is factually and technically correct.
I have nothing else to say, and therefore, this is my last post on this thread.
Best regards,
Mark
Mark,
The only thing I didn't like about your article is the incorrect information regarding Hasselblad and also the wording you use to describe Phase Detection AF.
If you feel the S2 gave you the best AF experience then it is not for me to argue.
I still disagree with some of your statements so, I will guess we will agree to disagree and all be happy.
Best Regards,
David
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Am I serious about seeing better testing photographs, yes, definitely because nothing is a buzz kill when reading about a $50,000 camera system than seeing shots off a roof on a rainy day.
... I like looking at pretty photographs, strange photographs, exceptional photographs and daring photographs. That's why we buy these things.
Strongly Agree! Sure, at first a few quick snaps and shots of brick walls are expected, but beautiful or interesting images are what many of us seek. Masterpieces, all? Of course not. They don't happen on demand. But interesting? Yes please. I always appreciate when those sharing results from these various cameras have an opportunity to actually shoot subjects as they would when making "real" images.
I don't intend this as a comment in reference to Marks article, only in a very general sense for the process overall. Thanks, B.C. (and alter ego) for bringing this up.
Cheers!
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Strongly Agree! Sure, at first a few quick snaps and shots of brick walls are expected, but beautiful or interesting images are what many of us seek. Masterpieces, all? Of course not. They don't happen on demand. But interesting? Yes please. I always appreciate when those sharing results from these various cameras have an opportunity to actually shoot subjects as they would when making "real" images.
I don't intend this as a comment in reference to Marks article, only in a very general sense for the process overall. Thanks, B.C. (and alter ego) for bringing this up.
Cheers!
A fashion photographer who used to be on RG and has been seen here at times sent me some Raws, when I was deciding to buy a back. I cannot name the guy, besides he seems to change names every day, but I'm really thankful for that. His images were breathtaking, and they also clearly showed me what I could expect from this type of product if used with studio flash. Also these images were much more useful to me than anything available from the manufacturers.
Edmund
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Hi,
One of the reasons microfocus adjustment is a good thing.
Best reagrds
Erik
And then there is wear and tear in the field. Bounce a mirror 50K times ....
Edmund
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Well, we certainly didn't clear up the little matter of depth of field at infinity!
The truth of what he was really thinking about, I imagine, is that because the depth of field is so wide at/near infinity, it becomes progressively more difficult for eye or machine to nail the precise plane of focus where it is so dificult to discern subtle differences.
Depth of focus: that 's a measurement that belongs at the film/sensor plane and has nothing to do with anything here, other than the fact that the longer the lens the deeper the depth of focus and the wider the lens the more shallow. You will discover that with your first trip into LF Land, if not LuLaLand!
God, it's hot in this stuffy room. I need a shower, feel a bit hungry but won't eat anything because it's too close to bedtime and I suffer from acid indigestion which threatens to choke me now and again when I forget and eat late. And to think, I used to be able to work until midnight, come home, devour a steak, french fries, peas, whatever else was going, go up to bed, do a hundred-and-twenty to a hundred-and-thirty press-ups and be up again in the morning for breakfast and in time to drive the kids to school. I can no longer do one press-up, I suspect, and am too scared to try. How time mocks us.
Rob C
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"...there is a f-stop correction depending on the focus distance."
this is interesting. since f-stop is defined by focal length/aperture diameter, are they making a slight aperture adjustment with respect to distance to compensate for the changing distance from lens center to image plane affecting exposure, like you do with a bellows extension?
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Well, we certainly didn't clear up the little matter of depth of field at infinity!
The truth of what he was really thinking about, I imagine, is that because the depth of field is so wide at/near infinity, it becomes progressively more difficult for eye or machine to nail the precise plane of focus where it is so dificult to discern subtle differences.
Depth of focus: that 's a measurement that belongs at the film/sensor plane and has nothing to do with anything here, other than the fact that the longer the lens the deeper the depth of focus and the wider the lens the more shallow. You will discover that with your first trip into LF Land, if not LuLaLand!
On the contrary, the depth of focus is critical to this discussion. For critical work, the plane of the image has to coincide with that of the sensor and also that of the focusing plane. The depth of focus gives a bit of tolerance. When you are focusing using the viewfinder and the focusing screen, the placement and alignment of this screen as well as the reflex mirror are critical, or else the image on which you are focusing will not represent the focus in the plane of the sensor. With Nikon dSLRs, the phase focusing detection autofocus sensors are in the bottom of the mirror well and the same considerations apply to these sensors as to the focusing screen.
When the object distance is relatively great, the depth of focus, t, is 2 * N * c, where N is the f/number and c the circle of confusion. If you use the commonly accepted (and liberal) circles of confusion of 0.029 mm and 0.047 mm for 35 mm and 645 (6 x 4.5 cm), the depth of focus is 0.23 and 0.38 mm respectively for f/4. The alignment of the lens must also be perfectly perpendicular to the sensor plane. With silver halide photography, the flatness of the film emulsion is also critical.
Regards,
Bill
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I think that this thread how now run its course. It's become too long, and crosses over into multiple topics.
I am therefore closing it, but if the topic continues to intrigue you, please feel free to start a new one.
Michael