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09-03-2010, 11:21 AM   #16
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QuoteOriginally posted by Lowell Goudge Quote
the point is, I think, that who ever edited and scanned the images probably did a ton of post processing to print in a magazine, on top of what ever processing, contrast and lighting adjustment the person who printed the shot origonally did,

It is hard to compare a 1:1 on this basis.
sorry, I forgot to tell that my father works in pre-press and he does all the processing for his pictures before sending them to press.

09-03-2010, 01:05 PM   #17
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QuoteOriginally posted by noou Quote
Still, what I don't understand is why his beautiful macro lens on the K20D is softer at f/22 than at f/11.
Oh, that much is easily explained by diffraction, and that affects images shot on film too. Although the specific aperture at which a lens become diffraction-limited does depend on format size, so I suppose there's probably a stop difference there. But it would still be the case that the lens would be softer at f/22 than f/11 on film too.

So the real question isn't whether/why results are softer at f/22 thanf/11 - that's always going to be true. The question is why they appear softer from the digital camera than the film. I can only guess that his digital workflow is not optimized to the same extent as his film workflow. He might not be applying appropriate sharpening for the intended output size, he might be introducing compression artifacts, etc. I mean, it's also the case that in *some* senses film can be said to outresolve an 14MP sensor but in other senses it doesn't, and it's going to depend in part on how the film is scanned. In this case, I suspect it's really coming down to the post processing.

Last edited by Marc Sabatella; 09-12-2010 at 08:51 AM.
09-12-2010, 06:28 AM   #18
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QuoteOriginally posted by Marc Sabatella Quote
Oh, that much is easily explained by diffraction, and that affects images shot on film too. Although the specific aperture at which a lens become diffraction-limited does depend on format size,so I suppose there's probably a stop difference there. But it would still be the case that the lens would be softer at f/22 than f/11 on film too.

So the real question isn't whether/why results are softer at f/22 thanf/11 - that's always going to be true. The question is why they appear softer from the digital camera than the film. I can only guess that his digital workflow is not optimized to the same extent as his film workflow. He might not be applying appropriate sharpening for the intended output size, he might be introducing compression artifacts, etc. I mean, it's also the case that in *some* senses film can be said to outresolve an 14MP sensor but in other senses it doesn't, and it's going to depend in part on how the film is scanned. In this case, I suspect it's really coming down to the post processing.
thanks a lot Marc.
I investigated a bit the technical sides of diffraction (e.g. on Ken Rockwell's site, there's an example in pictures which explains exactly what I'm talking about) and I concluded it is the main culprit of the softness.
As you suggested, I think that film grain can somewhat mask diffraction issues, while the K20D's cmos shows the resulting softness very clearly.

As for the 'flatter' look of digital images compared to the 'tridimensionality' of film ones (actually, for me it's only perceivable when pictures are printed), I think this issue is mostly related to the size and quality of the sensor compared to film (afaik, FF DSLRs should give equivalent depth, and dynamic range)
09-13-2010, 08:19 AM   #19
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I realize I'll get a lot of well-meaning explinations from professors of photographic technology against what I'm going to say, and they'll use some terms and calculation that are above my head, but I'm convinced diffraction (or the effects and appearances of it) are directly influenced by the quality of light.
In very practical applications, I have discovered to my own complete satisfaction that the more intense the light the less diffraction is noticed. I always shoot my DA 35mm macro Limited at f-22 when in macro mode, but I also fill it with intense, concentrated and diffused flash. The normal sweet spot with this lens is f-7.1.
I also have shot scenic scenes with my DFA 100mm macro where the sun angle was low and intense over my shoulder and suffered no noticable diffraction at f-14 and f-16. The sweet spot on this lens is between f-8 and f-9.
Photography is not about mathmatical calculations--it's all about the light.

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