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Author Topic: Thoughts on Medium Format Cameras  (Read 61568 times)

ErikKaffehr

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Re: Thoughts on Medium Format Cameras
« Reply #160 on: December 26, 2010, 05:22:39 pm »

Hi,

I'd just like to point out that Lloyd Chambers (Diglloyd) actually enjoys the Leica S2 very much, it's just that he finds it very hard to achieve critical focus. He seems to have this problem with two different bodies and several lenses. In recent testing he also found similar issues on Nikon D3X and D3s using Nikon 35/1.4 and 24/1.4 lenses. The Nikon obviously has live view and can focus at actual pixels or use contrast sensing AF.

As I see it, Lloyd Chambers has issues with AF on S2 and has samples to prove. Nicks (Devlin & Rains) and Mark Dubovoy don't seem to have issues. I cannot explain.

Best regards
Erik

Hi Bill, thanks and compliments of the Season to you as well.

Actually, there is no reason NOT to stitch medium format images - it depends on what kind of image you are making. I did a pano of the Toronto sky-line from the water front. There is NO WAY I could have encompassed all that material in a single shot with a wide angle lens on a DSLR and achieved the image quality at the size and resolution I printed it (5 feet long at something in the range of 300 PPI). It is three stitched P40+ shots. The detail in this pano, down to the texture of the concrete exterior of the CN Tower quite some distance away is truly quite remarkable. And it was made with the Phase One 75~150mm zoom lens, at 150mm, f/8.

While here, I would like to address two points from Bernard:

Bernard, yes, I too have had very annoying focus experiences with MF. I'm still to determine whether this is pilot error or something to do with the inherent nature of the technology. It can be amazingly sharp or truly crappy. Secondly, I think all this discussion of stitching is a bit of a red-herring. The real issue here is native image quality, before you start stitching anything. Much of the discussion of native image quality seems fixated on DxO, DigiLloyd and numbers about DR and pixel pitch. As I've mentioend before, I think the problem with DxO may have nothing to do with DxO itself, but with how people use it to convey lab work into making photographs; as for DigiLloyd, as I've said beforfe, all due respect to him, but I just don't find that Leica stuff he posted credible based on what I've personally witnessed that camera can do (anyhow, if he and Mark Dubovoy get together for some real-world photography using that system it would be extremely interesting to see what they come up with - jury out; finally, the numerical stuff: from the perspective of scientific method, what can always come back to bite us in the derriere are the hidden aspects which perhaps can be more determinative than the more tangible ones we think we know something about. You know that dilemma of not knowing what we don't know about. If you sit through a session with the Chief Technologist of Phase One - well not quite as good as sleeping at a Holiday Inn Express because he compresses very complex stuff into an hour or two - but you may get the point - there is a helluva lot more to making and programming a sensor than the stuff being discussed in this Forum, and until we know what it is and how determinative it is compared with the stuff we are discussing, we're not going to resolve what's better based on what little we know about what goes INTO it. We're on safest territory talking about comparisons of what comes OUT under conditions that are as comparable as we can make them. And even then we can have trouble. So I listen carefully to Nick Rains in his description of the tests he's done, similar to the sensible procedure Ray describes.

Gosh we're up to post a hundred and what - anything really conclusive yet? Maybe it's time to get out those knitting needles after all. :-)
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tsjanik

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Re: Thoughts on Medium Format Cameras
« Reply #161 on: December 26, 2010, 05:37:30 pm »

Some empirical data: I've had a 645D for about a week and was very concerned about my ability to use my MF A lenses.  After several tests, I'm convinced I can do as well as AF lenses (just much slower).  By way of example, here is a recent test of the Pentax 200mm A (not the best of the line) @f/8.  The crop of the lock is actual pixels (Approx. 140x140).  This is fairly typical of what I've seen so far.  Focus was on the lock.

Tom

NB No sharpening other than 50 in ACR
« Last Edit: December 26, 2010, 05:41:33 pm by tsjanik »
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BernardLanguillier

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Re: Thoughts on Medium Format Cameras
« Reply #162 on: December 26, 2010, 06:20:57 pm »

I did not understand your post, but my position is that if it cannot be heard, cannot be seen, cannot be smelled, cannot be touched, then for all practical purposes, one may as well consider it as not being there. Anyone claiming that it clearly is there, that cannot sense it in any way, are probably victims to "the emperrors new clothes"-effect.

This is my position on God, my position on (a lot of) audiophile equipment, and photography equipment. When people can show me a sensible side-by-side where I (or anyone else) can spot the difference, fine and good. If they can not, why bother?

Faith is indeed important. Both in high end audio and high end photography, some people do not trust measurements, they claim to hear/see things that are simply not apparent in measurement figures provided by top engineering facilities:
- some audiophile owners claim qualities to the music their equipment delivers that do not map well with objective measurements,
- some MF owners see magical qualities in the DR of their device than cannot be measured,

In both cases, faith in the value of money spent over-rides decades of science. In both cases rationality is swept aside by reference to their own quality as listeners or watchers, "my ear is better", "my eye is better".

Wait... faith... or bad faith? ;D

Is there a possibility that science is not measuring the right thing? That a real quality, not yet formalized, is perceived by some people with special sensibility? Yes, that is possible. What are the odds? Low, very low.

My personal bet is on the power of marketing rather than on the weakness of science.  ;)

By I agree Mark, this story is getting old as well, time to do some photography!  8)

Cheers,
Bernard

BernardLanguillier

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Re: Thoughts on Medium Format Cameras
« Reply #163 on: December 26, 2010, 06:36:29 pm »

finally, the numerical stuff: from the perspective of scientific method, what can always come back to bite us in the derriere are the hidden aspects which perhaps can be more determinative than the more tangible ones we think we know something about. You know that dilemma of not knowing what we don't know about. If you sit through a session with the Chief Technologist of Phase One - well not quite as good as sleeping at a Holiday Inn Express because he compresses very complex stuff into an hour or two - but you may get the point - there is a helluva lot more to making and programming a sensor than the stuff being discussed in this Forum, and until we know what it is and how determinative it is compared with the stuff we are discussing, we're not going to resolve what's better based on what little we know about what goes INTO it. We're on safest territory talking about comparisons of what comes OUT under conditions that are as comparable as we can make them. And even then we can have trouble. So I listen carefully to Nick Rains in his description of the tests he's done, similar to the sensible procedure Ray describes.

Gosh we're up to post a hundred and what - anything really conclusive yet? Maybe it's time to get out those knitting needles after all. :-)

Sure, let's put this to rest.

As far as the technology going into these products, I am pretty well aware about the complexity we do not see, but rest assured that folks at Canon, Sony and Nikon do just as much of it, they just don't communicate about it. That's the main difference with Phaseone. The Phaseone folks are approaching this from a B2B perspective that means a closer connection with your customers and therefore enables a small scale NDAed type of communication that is very powerful. I work in a similar B2B environment and our engineering does spend a significant amount of time with our customers. Besides the objective delivery of information, such communication also has a very efficient binding effect that generates a sense of belonging.

Focusing on the outcome is indeed best, whether it is measured or perceived. I am confident that average perception by third parties will converge to be very close to measure.

Anyway, what matters is happiness in the end and everybody around seem to be happy about their own choices. Perfect harmony will be reached the day we manage to respect choices different than our own. Since I acknowledge the value of MFDB as an excellent option, I feel that my part of the work is done.  ;D

Cheers,
Bernard

bjanes

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Re: Thoughts on Medium Format Cameras
« Reply #164 on: December 26, 2010, 06:36:50 pm »

Hi Bill, thanks and compliments of the Season to you as well.

Actually, there is no reason NOT to stitch medium format images - it depends on what kind of image you are making. I did a pano of the Toronto sky-line from the water front. There is NO WAY I could have encompassed all that material in a single shot with a wide angle lens on a DSLR and achieved the image quality at the size and resolution I printed it (5 feet long at something in the range of 300 PPI). It is three stitched P40+ shots. The detail in this pano, down to the texture of the concrete exterior of the CN Tower quite some distance away is truly quite remarkable. And it was made with the Phase One 75~150mm zoom lens, at 150mm, f/8.


Mark,

Your image sounds awesome, but it is not necessary to have a P40+ to take some very high resolution shots by stitching, as a Google search using the key words Megapixel and Images.

Here is a pretty impressive night shot of Chicago taken with 194 frames from a Canon 10D.

And here is a very impressive panorama of President Obama's inaugural speech composed of 220 frames from a Canon G10. I have read that a crop frame camera is actually better than a full frame model in many cases, since it uses only the central portion of the image.

And film is not entirely dead.

Regards,

Bill

 


« Last Edit: December 26, 2010, 06:42:56 pm by bjanes »
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BernardLanguillier

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Re: Thoughts on Medium Format Cameras
« Reply #165 on: December 26, 2010, 06:45:39 pm »

And here is a very impressive panorama of President Obama's inaugural speech composed of 220 frames from a Canon G10. I have read that a crop frame camera is actually better than a full frame model in many cases, since it uses only the central portion of the image.

With all due respect, that Obama picture is actually pretty awful and is in no way representative of the image quality achievable with stitching.

It is true that very high resolution can be achieved with compact digital also, but the quality of pixels with those really differs significantly from top DSLRs. This is both measured and seen (I used to own a G10 before it died too young).

As far as DX bodies being better, I believe indeed that a Pentax K5 or Nikon D7000 with a good FX lens like a Zeiss 50mm f2.0 probably offer the best comprise today between price and achievable image quality when stitching is considered since they have very clean shadows and therefore excellent DR. Besides, they have more DoF at the optimal apertures of the lenses and can therefore reduce the need for DoF stacking in some cases.

As a stitching platform, they are for sure very far ahead of my 2 years old D3x in terms of price to performance ratio and even farther ahead compared to MF.

Cheers,
Bernard

Mark D Segal

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Re: Thoughts on Medium Format Cameras
« Reply #166 on: December 26, 2010, 07:20:04 pm »

Mark,

Your image sounds awesome, but it is not necessary to have a P40+ to take some very high resolution shots by stitching, as a Google search using the key words Megapixel and Images.

Here is a pretty impressive night shot of Chicago taken with 194 frames from a Canon 10D.

And here is a very impressive panorama of President Obama's inaugural speech composed of 220 frames from a Canon G10. I have read that a crop frame camera is actually better than a full frame model in many cases, since it uses only the central portion of the image.

And film is not entirely dead.

Regards,

Bill


Bill, I never said it's *necessary* to have a P40+ for doing this. I was commenting on one of your previous statements to the effect that one wouldn't spend umpteen dollars to buy an MF and then stitch with it. And thanks but no thanks - I'll pas on stitching 194 frames and all the more so 220 in this day and age. But in the days of the Canon 10D, that is probably what he had to do to get that particular image of Chicago, which I agree is awesome. Amazing how fast this technology has been evolving. We can lose perspective.
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Nick Rains

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Re: Thoughts on Medium Format Cameras
« Reply #167 on: December 26, 2010, 10:25:26 pm »

[quote author=ErikKaffehr link=topic=49728.msg411002#msg411002 date=1293402159

As I see it, Lloyd Chambers has issues with AF on S2 and has samples to prove. Nicks (Devlin & Rains) and Mark Dubovoy don't seem to have issues. I cannot explain.

Best regards
Erik

[/quote]

I can't explain it either. But then again, I don't use AF much on either my Canons or the S2. I prefer to focus manually and, whilst I do get the occasional loose one, generally I'm happy with the sharpness. A big bright viewfinder and f2.5 lenses do help with the focussing.

The times that I have used AF on the S2, when shooting hand held, have resulted in as many sharp images as I get from my Canons. On a tripod, I turn off the AF.

UPDATE: I have just been shooting off some frames around the house, using AF at ISO640 and f2.5. It's miserable weather here in Brisbane so it's very gloomy in the house, hardly ideal AF conditions, yet the S2 worked fine and it seemed to nail the focus pretty well. Hardly a definitive test but reassuring at least. I'm not disputing Lloyds findings, they are what they are, but I'm not seeing it with my S2.
« Last Edit: December 27, 2010, 12:49:59 am by Nick Rains »
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ErikKaffehr

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Re: Thoughts on Medium Format Cameras
« Reply #168 on: December 27, 2010, 01:26:13 am »

Hi,

Sorry about the weather but happy about your results. Sweden, where I live is pretty gloomy this time of the year. We had a lot of snow the last month. Hopefully we get some sunshine today.

Best regards
Erik


UPDATE: I have just been shooting off some frames around the house, using AF at ISO640 and f2.5. It's miserable weather here in Brisbane so it's very gloomy in the house, hardly ideal AF conditions, yet the S2 worked fine and it seemed to nail the focus pretty well. Hardly a definitive test but reassuring at least. I'm not disputing Lloyds findings, they are what they are, but I'm not seeing it with my S2.
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hjulenissen

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Re: Thoughts on Medium Format Cameras
« Reply #169 on: December 27, 2010, 04:06:29 am »

How do you measure the benefits of using finely crafted hardware that simply gives pleasure by its use? If you get pleasure from using a tool, then there's a reasonable chance that you will do better work with it.

Using a camera that really feels good, and with a control setup that you, personally, find efficient and pleasing, can lead to greater enjoyment of your craft. This is not something that you can measure.
I think enjoyment is actually quite easy to measure. Depending on what you want to understand (and what variables you want to exclude from the test), you could give 20 persons a Leica and 20 persons a Panasonic where branding was removed, or where the image quality was identical, etc. Let them play with the toy for 2 weeks then use questionnaries to figure out what they feel. I would be surprised if the manfucaturers did not do something similar.
Quote
...if you have an 'expensive' camera, who's to say that the simple fact of owning a 'premium' product does not lead to better images simply because you just really enjoy using it.
I fully agree. But often one will see people claiming that their expensive camera (that they bought for hard-earned money) has amazing tonality, expressive dynamic range etc. They may be right, but they may also be mislead by their own feelings. Using scientific or semi-scientific tests of subjective response or physical measurements may settle this.
Quote
Photography is a fascinating hobby/profession because there is so much more to it than lab tests.
Lab tests may have limited relevance to photography, but I find it relevant to photography equipment.

-h
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hjulenissen

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Re: Thoughts on Medium Format Cameras
« Reply #170 on: December 27, 2010, 04:20:18 am »

Faith is indeed important. Both in high end audio and high end photography, some people do not trust measurements, they claim to hear/see things that are simply not apparent in measurement figures provided by top engineering facilities:
...
Is there a possibility that science is not measuring the right thing? That a real quality, not yet formalized, is perceived by some people with special sensibility? Yes, that is possible. What are the odds? Low, very low.

My personal bet is on the power of marketing rather than on the weakness of science.  ;)
Those people tend to forget that there are scientific methods of determining what you can see and what you can hear - not involving a single MTF measurement. The same tools are used by the food/drink industry to establish what wine people prefer, and if they can sense the difference between two wines.

If you are served two glasses of wine multiple times over a large time period and cannot sense any difference at all, it is probably not a question of "a real quality, not yet formalized", but a case of over-confidence in ones own senses coupled with (usually) knowledge of brand, feelings etc.

To venture a little less off topic:
How do you think along these lines when it comes to photography equipment? Two different cameras will typically be "different". They may have different weight, different size, different button layouts, and different color balance. This is trivial and may or may not matter for the user. Many users seems to be interested in the image quality in isolation (i.e. how good the image files out of the camera looks, or how good "optimally"post-processed files will look for certain camera settings. The fact that some cameras applies more noise reduction, while others have more sharpness seems irrelevant if one can emulate one with the other using reasonable photoshop skills and time.

I think it would be intereseting to have some tool (based on dcraw?) that could take two raw files from two different cameras of the same scene, and apply development parameters that make one look like the other. How different would cameras be then? I sometimes see two side-by-side images that are clearly somewhat different in exposure and white-balance presented as proof that one camera is inherently better than the other. Or two images with radically different tonemapping presented as proof that one camera has better dynamic range than the other.

-h

« Last Edit: December 27, 2010, 05:17:01 am by hjulenissen »
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douglasboyd

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Re: Thoughts on Medium Format Cameras
« Reply #171 on: January 13, 2011, 10:02:57 pm »

All,

I enjoyed this thread and would like to discuss Photo-Stitching using a real example.  A few months ago my wife asked me to produce a 30" x 90" photograph of the Hawaiian surf, more-or-less in the Peter Lik style (high saturated color).  This was intended to decorate our vacation condo in Waikiki.  So I dutifully set out to do this using my Sony A900 and a rented Gigapan Epic Pro.  Over a few days I visited several beaches in Hawaii and photographed with various lenses and photo-stitching to achieve 100-400 mega-pixels.   The result was several good pictures that look fine in smaller sizes, but do not qualify as "Fine Art" in the large size intended.  Since by definition photos of surf are not static, there is the obvious artifact that the waves do not line up.  There were a lot of other small but visible issues as well that might have been solved by using better software than that supplied in CS5 or Gigapan.   

In the end, I went back to Hawaii with a Fuji 617 camera and Velvia 100 film.  Velvia 100, not Velvia 50 because you need to have a reasonably fast shutter speed to freeze the water droplets in a surf picture.   I exposed the Velvia 100 at ISO200 to get deeper colors and to get even more film speed. I scanned using the Nikon 9000 focussed on film grain into a 500 megapixel 16-bit TIFF.  You have to use larger files with film scans than with digital due to the gradual slope in the MTF that film scans get, and then the need for a lot of sharpening.  The 1 Gigayte TIFF did stress Lightroom 3.3 and Photoshop CS5 almost to a standstill, and this required a few compromises in post-processing, but the result was reasonable.  Very similar to Peter Lik panoramas, but not as sharp as what is possible with digital photo stitching.  You don't notice the loss of sharpness at normal viewing distances, but see it when you move close.

My wife is happy with the final print, but I am now plan to purchase a Pentax 645D system to complement my Sony A900.  Based on my experience with A900 the Pentax should be able to support landscapes up to about 65" width with good sharpness, and should be close to the Fuji 617 in resolution.  But of course with the Pentax I will be able to shoot at ISO1600 which will be a great advantage when wading out in the surf and handholding a wide angle camera just inches above the active surf with good DOF and sharpness.

The attached photo is a down sized portion of the final print to show what I was trying to achieve that was not possible with 25mpix DSLR.  This was made at f11 and 1/250th hand-held a few inches above the water using a 90mm lens.

==Doug



 
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LesPalenik

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Re: Thoughts on Medium Format Cameras
« Reply #172 on: January 14, 2011, 12:29:50 am »

Quote
In the end, I went back to Hawaii with a Fuji 617 camera and Velvia 100 film.  Velvia 100, not Velvia 50 because you need to have a reasonably fast shutter speed to freeze the water droplets in a surf picture.   I exposed the Velvia 100 at ISO200 to get deeper colors and to get even more film speed. I scanned using the Nikon 9000 focussed on film grain into a 500 megapixel 16-bit TIFF.  You have to use larger files with film scans than with digital due to the gradual slope in the MTF that film scans get, and then the need for a lot of sharpening.  The 1 Gigayte TIFF did stress Lightroom 3.3 and Photoshop CS5 almost to a standstill, and this required a few compromises in post-processing, but the result was reasonable.  Very similar to Peter Lik panoramas, but not as sharp as what is possible with digital photo stitching.  You don't notice the loss of sharpness at normal viewing distances, but see it when you move close.

Doug,

This is a good example where stitching wouldn't work. It's very likely that some of the problem with loss of sharpness can be attributed to the lens/camera blur.
I have shot also many panoramic frames hand-held, some even from a moving boat, but you can't beat a solid tripod for sharpness, especially with a large-format camera.

The sharpness should be noticeably improved by shooting from a tripod and by scanning the film on a drum scanner or even on Imacon.
I have had printed several Fuji 617 images in 10 or 12 ft long size, and although I didn't compare them with digital stitched alternatives, they would pass a close scrutiny.
I don't know what gear is Peter Lik using in these days, but as I am aware, most of his large panoramas were shot with 617 film cameras.

 
« Last Edit: January 14, 2011, 12:44:17 am by LesPalenik »
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ErikKaffehr

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Re: Thoughts on Medium Format Cameras
« Reply #173 on: January 14, 2011, 01:03:00 am »

Hi!

Lloyd Chambers has tests of Pentax 645D, Leica S2 and Hasselblad H4D on his DAP site. There are comparisons with Nikon/Canon equipment. It's a pay site but worth the cost.

http://www.diglloyd.com/dap/index.html

Imaging resource has samples from the Pentax645D, some available as "raw". My summary of some findings is here: http://echophoto.dnsalias.net/ekr/index.php/photoarticles/51-a-closer-look-at-pentax-645d-image-quality

Regarding the DR aspect DxO-mark has good data.

I have seen very little downloadable images for comparing DR, but Lloyd Chambers (Diglloyd) made some raw images available for download from the Leica S2, and what I could see the S2 was inferior to the Nikon D3X on shadow detail.

On the other hand Phase One has also some images available for download. They have a high contrast image with a bridge from Melburn? photographed with both the Canon 1DsIII and the Phase One P65+. Here the P65+ outperforms the Canon 1DsIII by a wide margin with regard to DR.

The above conclusions are based on my own raw-processing.

Just a couple of more points.

- A larger sensor collects more photons and will be able to hold more electron charges. Photographic noise in digital images is mostly caused by the natural variation of the number of incident photons, called shot noise. Doubling the area will reduce the shot noise by a factor of 1.4.

- A camera having good DR would also have good high ISO performance.

- On the other hand, a larger format with top class optics would increase MTF for a given feature size, giving better "microcontrast" and better resolution of texture in the shadow areas. This is also an area there better lenses may show significant advantage. The Leica S2 lenses are said to be excellent designs, but I'd guess that some of the Phase One lenses are truly excellent, too.

In short, although I share your opinion on the value of lab testing I have seen enough evidence to convince me of the benefits of modern MF equipment. If it is worth the cost is an other issue, which is pretty much person dependent.

Best regards
Erik


Those people tend to forget that there are scientific methods of determining what you can see and what you can hear - not involving a single MTF measurement. The same tools are used by the food/drink industry to establish what wine people prefer, and if they can sense the difference between two wines.

If you are served two glasses of wine multiple times over a large time period and cannot sense any difference at all, it is probably not a question of "a real quality, not yet formalized", but a case of over-confidence in ones own senses coupled with (usually) knowledge of brand, feelings etc.

To venture a little less off topic:
How do you think along these lines when it comes to photography equipment? Two different cameras will typically be "different". They may have different weight, different size, different button layouts, and different color balance. This is trivial and may or may not matter for the user. Many users seems to be interested in the image quality in isolation (i.e. how good the image files out of the camera looks, or how good "optimally"post-processed files will look for certain camera settings. The fact that some cameras applies more noise reduction, while others have more sharpness seems irrelevant if one can emulate one with the other using reasonable photoshop skills and time.

I think it would be intereseting to have some tool (based on dcraw?) that could take two raw files from two different cameras of the same scene, and apply development parameters that make one look like the other. How different would cameras be then? I sometimes see two side-by-side images that are clearly somewhat different in exposure and white-balance presented as proof that one camera is inherently better than the other. Or two images with radically different tonemapping presented as proof that one camera has better dynamic range than the other.

-h


« Last Edit: January 14, 2011, 01:05:53 am by ErikKaffehr »
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Schewe

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Re: Thoughts on Medium Format Cameras
« Reply #174 on: January 14, 2011, 01:48:37 am »

- A camera having good DR would also have good high ISO performance.

Well, maybe...a lot of that depends on the quality of the amplification from native ISO to increased ISO.

Not all analog to digital converters (with amplification) are created equal.

Some of the qualification comes from what the noise signature of the original capture is. Adding amplification doesn't really add "noise" just the perceptibility of the noise. So, some A to D converters do better than others. At the moment, Nikon seems to be doing real well because the native ISO is already a tad higher (200 vs Canon's 100). Phase has lower native ISO at 50. And amp'ing the ISO of the A to D of a Phase capture without the +Plus tech kinda sucks...be sure you are comparing apples to oranges.
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BJL

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Re: Thoughts on Medium Format Cameras
« Reply #175 on: January 14, 2011, 06:09:23 pm »

- A camera having good DR would also have good high ISO performance.
The two do not exactly go together, and the Kodak 14n was a classic example: the combination of very large well capacity with higher than average dark noise (and maybe also low QE, due say to lacking microlenses) can combine to give good DR but poor noise performance in low light ("high ISO").

- A larger sensor collects more photons and will be able to hold more electron charges. Photographic noise in digital images is mostly caused by the natural variation of the number of incident photons, called shot noise. Doubling the area will reduce the shot noise by a factor of 1.4.
Agreed, with the qualification that you also need to deliver twice as much light to the sensor from the lens, which requires some combination of a longer exposure time and a larger entrance pupil size. The former can reduce sharpness due to subject or camera motion; the latter can reduce sharpness in parts of the image due to reduced DOF. Larger sensors and larger photosites are not a "free lunch" for improving IQ.
« Last Edit: January 14, 2011, 06:16:54 pm by BJL »
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ErikKaffehr

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Re: Thoughts on Medium Format Cameras
« Reply #176 on: January 16, 2011, 12:17:58 am »

Hi,

I sort of presume that 'horses for the courses' applies to MF. I presume that MF cameras are used in situations were they can perform optimally, like in studio or landscape and rather on tripod than free hand. DoF is still an issue of course.

MF digital backs have the additional advantage that they can be fitted to different camera body, possibly allowing Tilt and Swing or special very high resolution lenses.

Best regards
Erik

The two do not exactly go together, and the Kodak 14n was a classic example: the combination of very large well capacity with higher than average dark noise (and maybe also low QE, due say to lacking microlenses) can combine to give good DR but poor noise performance in low light ("high ISO").

Agreed, with the qualification that you also need to deliver twice as much light to the sensor from the lens, which requires some combination of a longer exposure time and a larger entrance pupil size. The former can reduce sharpness due to subject or camera motion; the latter can reduce sharpness in parts of the image due to reduced DOF. Larger sensors and larger photosites are not a "free lunch" for improving IQ.
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tho_mas

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Re: Thoughts on Medium Format Cameras
« Reply #177 on: January 16, 2011, 10:35:54 am »

Regarding the DR aspect DxO-mark has good data.

(...)

On the other hand Phase One has also some images available for download. They have a high contrast image with a bridge from Melburn? photographed with both the Canon 1DsIII and the Phase One P65+. Here the P65+ outperforms the Canon 1DsIII by a wide margin with regard to DR.
meanwhile I also looked at Peter Eastway's comparision of the 1Ds3 vs. P65 posted on the Phase site.
As these are published for comparision purposes I hope it's okay to post crops/screenshots of the images...?!?
source: http://www.phaseone.com/en/Downloads/Sample-images.aspx

The first attachment shows crops from both files pushed by around 3.5 stops in Capture One (1Ds3 image zoomed to 100%; P65 to 62% to roughly match the actual size).
The second attachment shows the same crops but the P65 pushed even further.
The third attachment shows the latter but a different crop from the capture.

No luminance NR but moderat colour NR was applied to both the captures.

Now, DxO shows a 1/3 stop screen and 1 stop print advantage in favour for the P65.
Doesn't make sense to me... clearly looks like several stops advantage for the P65 (only looking at the shadows here).
So, the comparision mediately also shows why MFD users often simply don't understand the DxO results.
It also might show that DxO's method is not appropriate for MFD RAW files as proprietray metadata is ignored (while being essential for the processing of MFD files). Not sure about that, but it seems so.

« Last Edit: January 16, 2011, 10:48:21 am by tho_mas »
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Ray

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Re: Thoughts on Medium Format Cameras
« Reply #178 on: January 17, 2011, 09:27:57 pm »

meanwhile I also looked at Peter Eastway's comparision of the 1Ds3 vs. P65 posted on the Phase site.
As these are published for comparision purposes I hope it's okay to post crops/screenshots of the images...?!?
source: http://www.phaseone.com/en/Downloads/Sample-images.aspx

The first attachment shows crops from both files pushed by around 3.5 stops in Capture One (1Ds3 image zoomed to 100%; P65 to 62% to roughly match the actual size).
The second attachment shows the same crops but the P65 pushed even further.
The third attachment shows the latter but a different crop from the capture.

No luminance NR but moderat colour NR was applied to both the captures.

Now, DxO shows a 1/3 stop screen and 1 stop print advantage in favour for the P65.
Doesn't make sense to me... clearly looks like several stops advantage for the P65 (only looking at the shadows here).
So, the comparision mediately also shows why MFD users often simply don't understand the DxO results.
It also might show that DxO's method is not appropriate for MFD RAW files as proprietray metadata is ignored (while being essential for the processing of MFD files). Not sure about that, but it seems so.



Makes perfect sense to me. In these comparison crops it is clear visually, and also accroding to F stop and shutter speed, that the P65 shots have about one stop greater exposure.

I frequently get the impression that photographers who attempt such comparisons between 35mm and MF do not appear to know what they are doing.

If you check the DXOMark test results first, you will find that ISO 50 and ISO 100 for both the P65+ and the IDS3 are the same sensitivity, ISO 44 (or 45) for the P65+ and ISO 73 for the 1Ds3 at both ISOs.

The comparisons you've shown are between the P65+ at F11, 1/60th and ISO 50, and the 1Ds3 at F11, 1/125th and ISO 100.

Of course the P65+ will have better shadow detail using twice the exposure at the same F stop.

If you check the DR figures for these two cameras, you will see that the P65+ at ISO 50 has a full stop better DR than the 1Ds3 at ISO 100, at equal image size.

If 1/60th sec exposure had been used with the 1Ds3 at ISO 50, the shadow noise would have been significantly improved and the highlights would have appeared blown, just as they do in the P65+ shot.
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ErikKaffehr

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Re: Thoughts on Medium Format Cameras
« Reply #179 on: January 17, 2011, 11:52:17 pm »

Hi,

I don't think that either the P65+ or the Canon had blown out highlights. Ray may be correct regarding the one stop difference in exposure. The histograms in Lightroom indicate this but Adobed has some bias that may falsify the comparison.

Best regards
Erik



If 1/60th sec exposure had been used with the 1Ds3 at ISO 50, the shadow noise would have been significantly improved and the highlights would have appeared blown, just as they do in the P65+ shot.
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