Diffraction versus Satisfaction

I remember a discussion on smaller f stops in which people were saying not to use the smaller ones like f/16 or f/22.
Got this email from Adorama today which disputes that idea.

http://view.e.adorama.com/?j=fe951c7...630d757217&r=0

Thoughts?

Completely agree and didn't even know it was an issue! I often shoot architectural and landscapes at smaller f/stops heck, even the first batch of studio shots posted in the critique forum were shot at f/16.

What I have been wondering is: people are concerned about - also in the debate of whether to use UV filter - the loss of sharpness and contrast (though it does not appear to be a significant loss). And, these days we have Photoshop and the like that allows us to do amazing things with our images. Is that little loss of sharpness and contrast really an issue at all today??

On some view cameras the lens full open is F24.....( 1meter lens, 1,000mm). and F62 or F92 are not unheard of on the shorter lenses < 300 mm. Pin hole cameras are examples of maximum diffraction you can have. This is just like the endless debate over the UV filter. (and it all comes down to personal choice).

The few times a did comparison shots at small apertures, I did notice substantial diffraction effects (I posted the results somewhere on this site). So much so that I'm one of those who intentionally stays away from f/22 and f/32 - and I'm a macro guy!

But if you need the DOF, it's a compromise - like everything else in photography.


Although the DOF-merge technique sounds promising if the application is right (stationary subject, time available for multiple shots, etc.)

I'm with Loupey. I've tested my lenses and found no reason to ever shoot a wide angle at f/22 because f/16 always looks better, even when extreme DOF is needed. That goes for modern zoom lenses and old prime lenses on film. If you need to slow down your shutter speed then by all means shoot at f/22 and don't worry about it. It's not a big difference. But I don't recommend doing it for DOF. I suppose your gear could be different than mine, so testing is really the only way to know for sure.

Paul

I was googling ant lions (I have them in my yard) and ran acros this site- http://www.waynesthisandthat.com/mybetterpictures.htm

He's using the stacking for increased DOF technique, so I imagine his subjects must be dead, I dunno. I didn't read the whole page, but I think the pic of the daddy long legs is particularly impressive.

BM

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Originally Posted by Loupey

But if you need the DOF, it's a compromise - like everything else in photography.

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I agree. For me, small apertures are pretty much a tool of last resort for what I shoot. It seems (just based on shooting and not actively trying to test a lens) that some lenses are better than others at small apertures. I had a 300mm that was awful at f32 (really f16 or more), but incredibly sharp wide open at f4.5. The 24mm wasn't good either but the 20mm was good all the way down.

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Originally Posted by photophorous

I'm with Loupey. I've tested my lenses and found no reason to ever shoot a wide angle at f/22 because f/16 always looks better, even when extreme DOF is needed.

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Correct me if I'm wrong, but my understanding of Loupey's position is that: if you need extreme DOF, by all means use f22, f32, etc., but be ready to accept the results caused by diffraction, i.e., image of poorer quality. It seems to me that he is saying there's no other in-camera way to obtain better DOF other than using smaller apertures. Also, my understanding is that you don't get as deep a DOF as that from f22 if you use f16. So, I don't see how you can get extreme DOF using f16 unless you use some other electronice post-processing methods.

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If you need to slow down your shutter speed then by all means shoot at f/22

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Yeah, but I suppose it's a given.

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It's not a big difference.

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Again, my question (which nobody seems to be answering yet):

if the difference is so small, given what Photoshop can do, is diffraction still an real issue these days?

Because if it is not, then it seems to me the recommendation of not using aperture smaller than f16 is moot. No?

It seems to me that, for every shot, we have to chose which gives the better image over the range of depth that we want in the photo - the DoF that can be obtained at the 'sweeter spots' with the lens or the smaller aperture with diffraction. This would also seem to be an individual choice since there are those that think sharper is always better and those that don't think this is necessarily true. - TF

Well, everything depends on each situation.

First off, sharpness and resolution are two different things. All sharpness is, is edge contrast. Resolution is the amount of detail you actually have captured. Diffraction hurts your resolution, and no amount of sharpening in post will ever bring back detail that was never recorded by your sensor (unless you are on CSI).

If you want a slow shutter speed, but also want maximum resolution (maybe a nice scene for a big print), you can use ND filters. Aslo, if you want massive DOF for some nice landscape, macro, or product photo, and can't or don't want to stop down for whatever reason, then that's what tilt shift lenses are made for.

Different tools for different jobs, but us mere mortals with limited budgets for our hobbies have to acccpt the compromises by using less than ideal tools for whatever job we are doing.

BM

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Originally Posted by AgingEyes

Again, my question (which nobody seems to be answering yet):

if the difference is so small, given what Photoshop can do, is diffraction still an real issue these days?

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I'll answer it: to me, the difference isn't so small. But, yes, I'm sure many with photoshop skills better than mine would be able to fix it up some/all.

But I'm all about image quality and if that means I give up a little DOF for the best possible IQ, I'll do that instead. Other than macros, I have yet to find a situation where I need such extreme DOF that couldn't be accomplished with a wide angle at "suitable" apertures.

Besides, I like a limited DOF to keep the viewer's eyes trained on where I want him/her to be looking :)

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Originally Posted by AgingEyes

Correct me if I'm wrong, but my understanding of Loupey's position is that: if you need extreme DOF, by all means use f22, f32, etc., but be ready to accept the results caused by diffraction, i.e., image of poorer quality. It seems to me that he is saying there's no other in-camera way to obtain better DOF other than using smaller apertures. Also, my understanding is that you don't get as deep a DOF as that from f22 if you use f16. So, I don't see how you can get extreme DOF using f16 unless you use some other electronice post-processing methods.

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In my experience, shooting with a lens that is 28mm or wider (35mm film equivalent), what you gain in DOF, going from f/16 to f/22, you loose in sharpness due to diffraction. I'm talking about shooting landscapes with subject matter in the close foreground all the way out to infinity. At f/22 you may have a more even level of sharpness across the image than at f/16. But at f/16, I usually find that sharpness in the worst part of the image is equal to the f/22 shot and the best part is very slightly sharper. If you're really concerned about getting the most out of your equipment, then test it and see for yourself. That's how I came to this conclusion. You may come to a different conclusion.

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Originally Posted by AgingEyes

Again, my question (which nobody seems to be answering yet):

if the difference is so small, given what Photoshop can do, is diffraction still an real issue these days?

Because if it is not, then it seems to me the recommendation of not using aperture smaller than f16 is moot. No?

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It all depends on how serious you are about getting the best image you possibly can from your gear. Practically speaking, you could say it's a moot point, unless you're making giant prints for gallery presentation. But if you can use photoshop to "fix" an image that suffers from diffraction, couldn't you use the same techniques to improve an image that doesn't suffer from diffraction so that it would be even better? I don't know. I'm not a photoshop wizard. I just prefer to try to get the best image possible in the camera. I'm not always successful, of course. I just don't like to shoot with plans of fixing it later.

Paul