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Author Topic: Digital backs offer more DR than 35mm sensors?  (Read 9978 times)
bjanes
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« Reply #40 on: January 30, 2010, 07:56:21 PM »
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Quote from: wildstork
... I would think this matter could easily be put to rest if the same landscape were shot under identical lighting conditions with a 22 megapixel digital back and, say, a Nikon D3x, using the best glass of equivalent focal lengths on each camera.  After all... it is often claimed that even the 22 mp digital backs will clearly beat the best of the 35mm offerings.  Shoot the damned images at = iso, process in Capture One (or whatever the best software may be for the that given camera) and print them out at 24x36" on fine art paper.
The main problem with your proposal is that the best glossy prints have a dynamic range of 8 stops at best, and the DR of fine art paper is considerably less. To show the entire DR of the capture would require tone mapping during the rendering, and good rendering is art as well as science (see Karl Lang: Rendering the Print: the Art of Photography). This brings up the raw developer and its settings as well as the skill of the photographer.

Shooting at the same ISO would not be advisable. At high ISO the D3x would blow away a P65+. I would suggest base ISO, since if DR is critical, one should optimize it, using a tripod if necessary. For landscapes most would use a tripod anyway.

You would likely want to normalize for print size as DXO does, but 24 by 36 inches is too much for a D3x, since the print resolution would only be 168 pixels/inch. Also, 3:2 is not the aspect ratio for most MFDBs, and you would have to crop the image.The difference in resolution with a P65+ would be obvious. 22 MP is not state of the art for MFDB. You would be comparing old vs new technology if you compared a 22 MP back with a D3x.

Then you would have to make certain that the photographed scenes are identical and that the exposure was optimum with the sensor at saturation so that the full DR of the camera is used. You can't rely on camera histograms or histograms on the raw converter.

As Michael showed with his megapixel shootout, controlling all the variables and reaching subjective conclusions was difficult even for those highly skilled and knowledgeable photographers. Finally, as Michael pointed out, regardless of the test procedures, there will be nit pickers.

Nonetheless, the test you proposed would be interesting. Other things being equal, a larger sensor would likely come out on top.

Bill
« Last Edit: January 30, 2010, 08:04:01 PM by bjanes » Logged
wildstork
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« Reply #41 on: January 30, 2010, 10:06:24 PM »
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Quote from: bjanes
"The main problem with your proposal is that the best glossy prints have a dynamic range of 8 stops at best, and the DR of fine art paper is considerably less."

That's clear to me as well, Bill.  It punishes both 35mm and mf digital equally, so there is no advantage to either.  I print exclusively on fine art paper.  Others prefer glossy or premium luster.  Two prints could be made of each and this would make for an even more interesting comparison.  I simply prefer to judge the quality of both files on a print rather than on screen.

"To show the entire DR of the capture would require tone mapping during the rendering, and good rendering is art as well as science (see Karl Lang: Rendering the Print: the Art of Photography). This brings up the raw developer and its settings as well as the skill of the photographer."

Personally I'd trust both Michael and Jack with this task... not that others on this and other forums wouldn't be competent as well.  The point is not to make this such a difficult exercise that you hamstring the whole thing with a protracted exercise in nit picking.  If MF digital is clearly superior it shouldn't require the efforts of Joseph Holmes to make this obvious.  If the difference is barely visible on fine art paper, those who print with fine art paper can save themselves a ton of money and headaches by sticking with 35mm... if that's where they're coming from.

"Shooting at the same ISO would not be advisable. At high ISO the D3x would blow away a P65+. I would suggest base ISO, since if DR is critical, one should optimize it, using a tripod if necessary. For landscapes most would use a tripod anyway."

I never suggested a test where the D3x and mf digital are shot at 3200 iso.  The point here is to shoot both at their optimum iso as that's the iso one would use when making a large fine art print.

"You would likely want to normalize for print size as DXO does, but 24 by 36 inches is too much for a D3x, since the print resolution would only be 168 pixels/inch. Also, 3:2 is not the aspect ratio for most MFDBs, and you would have to crop the image.The difference in resolution with a P65+ would be obvious. 22 MP is not state of the art for MFDB. You would be comparing old vs new technology if you compared a 22 MP back with a D3x."

Optimize the print dimensions however you like.  One is 3:2 and the other is 4:3.  Get on with it.  No one has ever alleged that the best in 35mm digital is equal to a 65 mp back.  Certainly not me.  The numbers who have stated that a 22 mp digital back will beat the best 35mm has to offer are legion.  This isn't about proving a P65+ is better than a D3X at optimum iso.  I don't think anyone disputes that so why cook the books in favor of the P 65+?  A 22 mp back is not old technology as many are still doing their commercial work with an Aptus with 22 mp.  It was still being sold when the D3X was released.  The point is about being able to see superior IQ at optimum iso and deciding whether the constraints of MF digital are worth the effort in switching platforms.  If a 22 mp digital back will prove superior... a p30+, P39+, P40+ and the Dalsa equivalents will only make that more obvious.   I'm sure many have this question.  

"Then you would have to make certain that the photographed scenes are identical and that the exposure was optimum with the sensor at saturation so that the full DR of the camera is used. You can't rely on camera histograms or histograms on the raw converter."

Gee... lets just make this so impossible it's not worth the effort to do any test!  Your make this sound like an exercise in pissing up a rope.  Some of us would really like to see such a test so we can lay this dog to rest.  You make it sound like you'd rather contribute to thread after thread on the same topic and throw obstacles in the path of anyone who is trying to get answers.  Your prerogative and you're entitled to it.  I have better things to do with my time.
I'm looking for definitive answers here.

"As Michael showed with his megapixel shootout, controlling all the variables and reaching subjective conclusions was difficult even for those highly skilled and knowledgeable photographers. Finally, as Michael pointed out, regardless of the test procedures, there will be nit pickers."

Especially when some of those "nit pickers" base their arguments on misquoting the actual resolution of the scans after repeated corrections by Michael!

"Nonetheless, the test you proposed would be interesting. Other things being equal, a larger sensor would likely come out on top."

Bill

I think you're right on that last point, Bill.  My interest is in seeing just how noticeable the difference is on fine art paper.  Others will prefer glossy.  I picked an arbitrary size of 24x36 as it would tell us a lot about the quality of those mf digital pixels on a 22 mp digital back... just as it would about the D3X's output.  I don't think there are many who have shot with a 22 mp mf digital back who would think they're at a disadvantage in such a test.  Side by side prints are where the rubber meets the road.  

Lawrence



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Graeme Nattress
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« Reply #42 on: January 31, 2010, 06:38:25 AM »
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Quote from: wildstork
I think you're right on that last point, Bill.  My interest is in seeing just how noticeable the difference is on fine art paper.  Others will prefer glossy.  I picked an arbitrary size of 24x36 as it would tell us a lot about the quality of those mf digital pixels on a 22 mp digital back... just as it would about the D3X's output.  I don't think there are many who have shot with a 22 mp mf digital back who would think they're at a disadvantage in such a test.  Side by side prints are where the rubber meets the road.  

Lawrence

If you're interested in an accurate comparison of DR, then a print is going to hinder you rather than help you. A print has such much less dynamic range than today's good cameras that even with a very carefully constructed development curve you're going to have to get into very careful secondary colour correction - carefully brightening dark areas (by hand or by whatever technique) - to map the large DR of the camera down onto the smaller DR of the screen or a print.

Graeme
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Jack Flesher
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« Reply #43 on: January 31, 2010, 08:10:06 AM »
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The captured DR maps to the print, so if you saved highlights and shadows in a given capture, they have a chance to map to the print and while compressed, you can usually maintain visible tonal separation across the entire capture value even though it's compressed -- at least you can if you know what you're doing in post.  In the case where the captured image fully clipped shadows and/or highlights and they cannot be processed out, compression at the print not only leaves them clipped, but in most cases the clipping edge is more obvious due to the compression, leaving visible edges where the blocked shadows and blown highlights transition in the print. (And if you've seen it, you know it's an ugly result.)  

Capturing versus rendering.  While the captured DR at the sensor may be measurably larger for camera A than it is for camera B, camera B's combination of file properties and processing software -- and the user's ability to better manipulate it -- can allow for a superior final rendering of a total DR for the purposes of that print. Thus when you compare the final prints, camera B's DR result appears superior to camera A's.  

For *my* purposes, which is a print, I'll choose to use camera B because it renders superior DR, and I am able to get more of it visually into the print, usually represented by smoother transitions in the deep and high values.  Granted, my absolute color values may not be as accurate in the deep shadows or bright highlights as the camera A result, but B's transition values can still look smoother/better for the aesthetic I'm after...
« Last Edit: January 31, 2010, 10:14:53 AM by Jack Flesher » Logged

EricWHiss
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« Reply #44 on: February 04, 2010, 01:40:57 PM »
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Quote from: Graeme Nattress
If you're interested in an accurate comparison of DR, then a print is going to hinder you rather than help you. A print has such much less dynamic range than today's good cameras that even with a very carefully constructed development curve you're going to have to get into very careful secondary colour correction - carefully brightening dark areas (by hand or by whatever technique) - to map the large DR of the camera down onto the smaller DR of the screen or a print.

Graeme

This is probably true to some extent when just looking at an image's light to dark component, but if you look at the image from a sideways path across the hues instead of luminance, you'll see one area of difference between camera platforms that goes largely without discussion. The richness of color or tonality that a camera is able to capture is really important to an image and IMHO contributes a significant palpable depth.  So while most papers have a contrast of 100::1 or 200:1 and the DR (in luminance terms) is compressed, in some cases the subtle color transitions in things like flowers, plants, sky, and skin can still get through intact from camera to print.   It seems that my CCD based cameras - Ixpress 528c, phase p20, and leica DMR all do a much better job at this than my canon 5d2.
« Last Edit: February 04, 2010, 01:41:24 PM by EricWHiss » Logged

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Fritzer
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« Reply #45 on: February 05, 2010, 03:01:28 PM »
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Oh look, it's an MFDB vs. 35mm thread, how exciting !

They've become so rare, ....
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