Luminous Landscape Forum
Equipment & Techniques => Medium Format / Film / Digital Backs – and Large Sensor Photography => Topic started by: BillOConnor on December 30, 2010, 10:06:11 pm
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After reading Mark Dubavoy's posting on medium format digital cameras, and following his links, it seems that the Mamiya/Phase One cameras have issues with their backs not being properly mounted for accurate focus, but the Leica S2, owing to it's design does not suffer from these problems. Has anyone had
the chance to look at the Pentax 645D in this regard since it is closer in design to the Leica than to the other cameras of its ilk?
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After reading Mark Dubavoy's posting on medium format digital cameras, and following his links, it seems that the Mamiya/Phase One cameras have issues with their backs not being properly mounted for accurate focus, but the Leica S2, owing to it's design does not suffer from these problems. Has anyone had
the chance to look at the Pentax 645D in this regard since it is closer in design to the Leica than to the other cameras of its ilk?
In three years heading Tech Services for one of the largest Phase One dealers I've seen six or so lenses need to be sent in to Phase/Mamiya for focus calibration. So I'm here to tell you it's not a non issue, but:
1) it's much much more rare than your statement implies
2) it's not impossible with Leica either [search forum posts here and at getdpi for at least one report of similar with S2]
3) Focus recalibration is covered under warranty, can be done in the US, and takes only 2-3 days to turn around once received at the service center
I would love to see a feature similar to Nikon/Canon micro-adjust on a future Phase One body (or Leica/Hassy/Sinar etc).
Doug Peterson (e-mail Me) ([email protected])
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Doesn't the Pentax have micro-adjust?
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Doesn't the Pentax have micro-adjust?
It's listed in the tech specs for the K-5, but not the 645D. Can an owner confirm?
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It's listed in the tech specs for the K-5, but not the 645D. Can an owner confirm?
The 645D has custom function C33 AF Fine Adjustment. But this is for the whole body, not for individual lenses.
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I know you have all read Mark's (Dubovoy, sorry Mark) piece where he says the Alpa system allows the backs to be shimmed, which implies to me that
the issue is not with the lenses. I'm sure it could be. I wonder if the Leaf backs also benefit from shimming. It seems that a person would have to design
a test that isolated the variables--and there are several. The tests showing images made with shimmed and un-shimmed backs on an Alpa camera
were sobering, to say the least, considering the costs of the equipment we're dealing with.
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After reading Mark Dubavoy's posting on medium format digital cameras, and following his links, it seems that the Mamiya/Phase One cameras have issues with their backs not being properly mounted for accurate focus, but the Leica S2, owing to it's design does not suffer from these problems. Has anyone had
the chance to look at the Pentax 645D in this regard since it is closer in design to the Leica than to the other cameras of its ilk?
Bill,
I have the 645DF and the Schneider LS lenses. Not once has this camera missed focus for me, not even at F2.8.
David
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Hi,
The Leica is shimmed at the factory, but I'd think that also applies to most professional equipment. I was surprised that Mark needed do as much shimming. Maybe the Alpa is intended to be customer adjusted. I have read that Phase One sensors are adjusted to with 0.015 mm but that's only the tolerance on the sensor vs. the mounting plate at the time the back leaves the factory.
You may checks this very fine article: http://www.josephholmes.com/news-medformatprecision.html
It seems that different persons have very different experience with AF-performance.
Best regards
Erik
I know you have all read Mark's (Dubovoy, sorry Mark) piece where he says the Alpa system allows the backs to be shimmed, which implies to me that
the issue is not with the lenses. I'm sure it could be. I wonder if the Leaf backs also benefit from shimming. It seems that a person would have to design
a test that isolated the variables--and there are several. The tests showing images made with shimmed and un-shimmed backs on an Alpa camera
were sobering, to say the least, considering the costs of the equipment we're dealing with.
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I guess the best plan is simply to buy the camera you like and use it.
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It seems that different persons have very different experience with AF-performance.
I think a lot of what we see with focus comes from the style/way we shoot. If I go to a tripod, (with any camera) my focus improves 4 fold.
If I hand hold close to wide open, obviously the results are more limited, (once again with any camera).
What I do find amazing is I have multiple Contax bodies and two Phase backs and previous to this had two different Leaf backs.
I've never seen an issue with focus on any of them and when I had the Leaf, Leaf of America was kind enough to take my bodies and lenses and check all of them.
When I think about a third party back fitting on a out of production camera and the focus is tack sharp, I find that somewhat amazing, given the critical nature of digital.
IMO
BC.
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Hi,
It's also my experience that AF works reasonably well, but I mostly shoot at f/8.
Some people get absolutely top of the class lenses from Leica and Zeiss and shoot them at near full aperture and expect to have exact focus. The persons (Lloyd Chambers, Joseph Holmes and Mark Dubovoy) complaining about focusing and misalignment are known for meticulous work. They also have the best lenses with the highest resolving sensors.
I guess that our mileage may vary, even if I'm somewhat surprised it varies that much.
Best regards
Erik
I think a lot of what we see with focus comes from the style/way we shoot. If I go to a tripod, (with any camera) my focus improves 4 fold.
If I hand hold close to wide open, obviously the results are more limited, (once again with any camera).
What I do find amazing is I have multiple Contax bodies and two Phase backs and previous to this had two different Leaf backs.
I've never seen an issue with focus on any of them and when I had the Leaf, Leaf of America was kind enough to take my bodies and lenses and check all of them.
When I think about a third party back fitting on a out of production camera and the focus is tack sharp, I find that somewhat amazing, given the critical nature of digital.
IMO
BC.
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In reply to Doug's comment above, the Sinar Hy6 has focus micro adjust, in the latest firmware (update needs to be done in Zurich). I had this done, all my lenses were calibrated on a bench and I was given a certificate showing the adjustments for all three of my lenses (+1 for the 80 mm, -6 for the 180mm and -7 for the 50 mm). Regards, Martin
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Some people get absolutely top of the class lenses from Leica and Zeiss and shoot them at near full aperture and expect to have exact focus. The persons................
All I can tell you is owning Contax, Leica, about every canon, Panasonic, Nikons, the only lens I've seen that had definate focus issues was the 90mm Leica on the M8, I sent it in, waited a month, and it still back focused.
Now, I'll admit sometimes autofocus on the Contax can be off, then I switch to manual and it's on, sometimes manual seems off, I switch to autofocus and it's on, but never have I had both auto and manual on the Contax be out of focus.
Still, everytime somebody tells me about focus, I say get a tripod. Even if you shoot moving subjects (I only shoot people) a tripod will increase the focus by 1000%.
I am almost sure that nearly every modern camera, from the blad, the Phase has very good focus. I doubt seriously at those price points that focus would be an issue any company would want publicized.
IMO
BC
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All I can tell you is owning Contax, Leica, about every canon, Panasonic, Nikons, the only lens I've seen that had definate focus issues was the 90mm Leica on the M8, I sent it in, waited a month, and it still back focused.
Now, I'll admit sometimes autofocus on the Contax can be off, then I switch to manual and it's on, sometimes manual seems off, I switch to autofocus and it's on, but never have I had both auto and manual on the Contax be out of focus.
Still, everytime somebody tells me about focus, I say get a tripod. Even if you shoot moving subjects (I only shoot people) a tripod will increase the focus by 1000%.
I am almost sure that nearly every modern camera, from the blad, the Phase has very good focus. I doubt seriously at those price points that focus would be an issue any company would want publicized.
IMO
BC
Hah! the fallacy of induction!
Edmund
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I wonder if the Leaf backs also benefit from shimming.
I would think that any back system could be shimmed. After all, its just mylar/laminates/etc. of different thicknesses inserted between back and body.
Issue would be if back is already too far from sensor plane where shims would only place unit further...
You can do the "Alpha infinity" on any system if you want to know for sure (search for videos on youtube). Worth doing, if for no other reason than to clear your mind.
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As in 'inductive reasoning'?
Happy New Year, Keith; did Mini manage the snows? Did you manage the snows?
Rob C
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As in 'inductive reasoning'?
Yeah, Bertrand Russell's chicken :)
Edmund
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Yeah..................
Edmund
A few years ago a 3rd assistant smugly told me he knew he would be a great photographer because he always sees better images than the photographers he works with.
I kind of thought about that and and said, yea, I'm sure you do, but keep in mind that you don't have "your" 80 grand resting on the shot. At that point the world gets different.
I can't tell you what works for focus for others, I just know that sometimes autofocus on all cameras is brilliant, other times, it's dead stupid and usually what will manual focus for one session doesn't work as well for the others . . . and vice-versa.
I think that's why you constantly read one photographer who says my ____ ____ is just dead on perfect and the next one says the same camera is for s**t.
It all depends on the circumstance.
IMO
BC
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A few years ago a 3rd assistant smugly told me he knew he would be a great photographer because he always sees better images than the photographers he works with.
I kind of thought about that and and said, yea, I'm sure you do, but keep in mind that you don't have "your" 80 grand resting on the shot. At that point the world gets different.
I can't tell you what works for focus for others, I just know that sometimes autofocus on all cameras is brilliant, other times, it's dead stupid and usually what will manual focus for one session doesn't work as well for the others . . . and vice-versa.
I think that's why you constantly read one photographer who says my ____ ____ is just dead on perfect and the next one says the same camera is for s**t.
It all depends on the circumstance.
IMO
BC
You left out the best bit: what's the assistant doing now?
Rob C
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Assisting.
But in all fairness he does have what it takes if the cards fall right.
BC
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Guys, Happy new year to all.
I'm completly blured in this thread and do not catch this level of english.
Is it a thread about focussing?, assistants?, S2?, 645D? (I guess the 645D is a non-assistant-camera), about snows or mini snows?
It seems to be a thread about high precision, focusing.
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I think this is a very fuzzy and unfocused thread - ok you can call it a rope used to ring in the new year :)
Edmund
Guys, Happy new year to all.
I'm completly blured in this thread and do not catch this level of english.
Is it a thread about focussing?, assistants?, S2?, 645D? (I guess the 645D is a non-assistant-camera), about snows or mini snows?
It seems to be a thread about high precision, focusing.
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Hi,
Regarding inglese, these pages may help ;-): http://es.wikipedia.org/wiki/Inducción_matemática (oh, just kidding)
Regarding the precision in focusing it is quite important. Would you invest like 300 kUSD in a camera you would expect it to focus correctly. Some authors on the net have found that consistent focus is hard to achieve. One of the authors, Lloyd Chambers has found the issue on two different samples of Leica S3, Leica M9, Pentax 645D (to lesser extent, Sonya Alpha 900 with 135/1.8 Sonnar and also some f/1.4 wide angles on Nikon D3X and D3s.
C'tein had also an article on the issue (which I cannot find) and Joseph Holmes discusses the issue:
http://www.josephholmes.com/news-sharpmediumformat.html
http://www.josephholmes.com/news-medformatprecision.html
On the other hand, Mark Dubovoy is quite impressed by AF on the Leica S2, and "bcooter" found no significant issue on his equipment, except a single lens from Leica that had back focus.
Best regards
Erik
Guys, Happy new year to all.
I'm completly blured in this thread and do not catch this level of english.
Is it a thread about focussing?, assistants?, S2?, 645D? (I guess the 645D is a non-assistant-camera), about snows or mini snows?
It seems to be a thread about high precision, focusing.
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The 645D has custom function C33 AF Fine Adjustment. But this is for the whole body, not for individual lenses.
Incorrect. The 645D stores fine focus adjustment for each lens type, just not for individual copies of the same lens.
- N.
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I guess the best plan is simply to buy the camera you like and use it.
Always.
Mike.
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Incorrect. The 645D stores fine focus adjustment for each lens type, just not for individual copies of the same lens.
- N.
You are correct. I should have read the manual. I only looked in the custom menu. My mistake. :-[
The menu is a lite bit misguiding.
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Anyway, I'd say that focus issues differences hit visibly at 8x10 size, while resolution waits till A3, so a good dSLR will beat MF in everyday use, and MF will demolish a dSLR in demanding applications.
Edmund
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... MF will demolish a dSLR in demanding applications.
Probably so if your sole criterion for "demanding applications" is higher resolution/sharpness/detail in a single frame than the D3X, A900 or A850 give, but there are many other demands in professional and serious amateur photography (like anything involving high speed, be it high shutter speed or high frame rate or even just fast changes of focal length between shots), and some of these are handled far better by DSLRs in 35mm format, or even smaller.
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Test. Just checking my portfolio link.
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Hi,
In my view there is no way around the fact that a larger sensor can collect more photons and offer better MTF of for a given size of detail. Now, DSLRs may be more refined than MFDBs in several areas. Let's not forget that DSLR makers nowadays are powerhouses of electronics, at least Canon, Sony, Panasonic and Samsung but even Nikon is a giant compared to Phase One or Leica.
Depending on shooting situation either system may be preferable. But it's quite obvious that in an optimal setting MF can play to it's strength.
On the other hand I don't really think there is some magic behind MFDBs (except the photographer, of course).
Stitching is not always possible. Some programs, like Autopano Pro, are good at handling things that move but water and waves are still difficult. On the other hand, stitching is always an option. My gear fits in my pockets, except the camera, of course.
Would I buy an MF system I would be concerned about lack of live view. I'm certainly concerned about not having it on my Alpha 900.
Best regards
Erik
Probably so if your sole criterion for "demanding applications" is higher resolution/sharpness/detail in a single frame than the D3X, A900 or A850 give, but there are many other demands in professional and serious amateur photography (like anything involving high speed, be it high shutter speed or high frame rate or even just fast changes of focal length between shots), and some of these are handled far better by DSLRs in 35mm format, or even smaller.