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Clearly, photography is basically nearly impossible ....

Manglesphoto Loc: 70 miles south of St.Louis

In the mind me thinks

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

If you are a landscape photographer, diffraction is more of a problem than if you shoot macros.

Details in rocks and tree leaves and other "stuff" when shot at a distance will get irrevocably lost when there is diffraction. Mild diffraction can be dealt with by manipulating micro or high frequency contrast, but severe stuff will make you think your camera is broken.

On the other hand, when shooting macro or close up, your image will have detail that is unexpected, such as the setae (hairs) on insect legs, barbs and barbules on a bird's feather, etc. Even a fairly small aperture will still capture this with surprising detail. Of course, opening the lens to the optimum aperture will do a better job, especially in a side by side comparison.

Diffraction is a term used to describe the phenomenon of how light spreads after going through a hole. Smaller hole=more spread=more diffraction=less detail captured=softer image. Diffraction is the antithesis of the pursuit of sharpness - particularly those who choose pricey gear, don't use UV or clear filters in the light path, and obsess over precise focus by resorting to the fine focus tuning features in their cameras.

In the simplest of terms diffraction is based on lens aperture and pixel size or Circle of Confusion - these are easily represented as precise measurements Airy Disk diameter for the lens, and Pixel diameter or CoC for the camera's sensor. Smaller apertures will record a larger a Airy Disk size, and vice versa. A camera with a large pixel size - cannot resolve really fine detail anyway, so it can tolerate a larger Airy Disk than a camera that has a smaller pixel. When the Airy Disk exceeds the size of the CoC, there will be diffraction. If the amount the size of the larger Airy Disk is close to the size of the CoC, the loss of sharpness will be modest. The larger the Airy Disk is relative to the CoC, the higher the image degradation. Typically, an expensive lens is equally susceptible to the effects of diffraction as a more modestly priced lens.

Diffraction is constant for subject to camera distance, aperture and pixel size and has nothing to do with lens brand, focal length or camera brand - btw - so F22 on one camera and lens will be EXACTLY the same as F22 on another camera and lens as long as the pixel size is the same. So if one were using a 50mm lens at F22, the same amount of diffraction would be present as if one were using a 200mm lens at the same aperture on the same camera, or camera with the same pixel size.

When you dig deeper into how diffraction works, there are other factors that will contribute to the perception of sharpness - overall sensor size/print size (a smaller sensor will seem less sharp when you try to make a big print), viewing distance of the final image (the greater the distance between the image and the viewer the harder it will be to pick up flaws), image content (images with a lot of texture and detail will look worse than a wide-view sunset), viewer's eyesight, print surface, lighting where prints are viewed, etc.

This is a very thorough treatment of the subject of diffraction, and offers some simulators and calculators to help promote a better understanding, and more importantly, dispel some widely held myths.

https://www.cambridgeincolour.com/tutorials/diffraction-photography.htm

camerapapi Loc: Miami, Fl.

I can only speak in my behalf and the following is my experience with diffraction.

When I need f22 I do not hesitate a second on using it and the same goes with f16. If indeed there is a deterioration of image quality it will be evident with pretty large enlargements. My usual prints when I enlarge an image is 13x18 and I have never noticed to my eyes a deterioration in quality.
If using digital many cameras will correct for diffraction if using JPEG files.

User ID

Please clarify. Where you compare a 50 to a 200 you write “same aperture” but just prior to that you put them both at f:22. I know that you know the difference between same f:stop and same aperture (physical hole size).

The abrupt change in your terms is what I ask you to clarify. After all, if a 50 is at f:22 then a 200 at the same f:stop is obviously also at f:22. But if the 200 is at the same aperture size then it will be at f:90.

So were you using “same aperture” as vernacular for “same f:stop”, or did you mean “same aperture size” (much higher f:stop) ? I’ve always understood that when dealing with diffraction (and also DoF) that aperture means “aperture hole size” and not “relative aperture” which acoarst means “f:stop”.

I would expect similar diffraction at similar aperture size, not at same f:stop, regardless of FL.

ELNikkor

I never noticed it, and would not even know it existed if I didn't read about it here.

Leitz Loc: Solms

Anyone capable of doing their own thinking would test their lenses at each aperture and avoid mixed feelings.

zug55 Loc: Naivasha, Kenya, and Austin, Texas

"Is Diffraction A Real Problem?" Not if you don't see it.

Each lens has a sweet spot, often about two stops from the largest aperture, usually around f/5.6 or f/8. As you decrease aperture, most lenses get a little softer and grainier, particularly in the f/16 to f/22 range--an issue often described as diffraction. This will depend on the lens you use and the actual image--you may see more of it in images with a larger dynamic range.

Obviously, there are good reasons why you sometimes want to shoot at f/16 or f/22, like to increase depth of field.

Diffraction is real. Is it a problem? There are many answers to that question, as the many responses to your post show. Often there is a tradeoff involved. Some lenses perform worse than others. And some photographers have a higher tolerance for it than others.

burkphoto Loc: High Point, NC

1) It’s real, and can be a problem.

2) The exact aperture where it becomes noticeable varies with sensel density, format size, magnification, and subject matter.

3) Most lenses have an “optimal performance aperture” and an optimal performance range of apertures. Staying within the range keeps diffraction to a minimum.

4) Only testing with your camera, lenses, and typical subject matter can reveal your personal range of diffraction tolerance.

As with most things in life and photography, “It depends...” is the proper answer.

TriX Loc: Raleigh, NC

first, let me add that the effect of diffraction is format dependent - f22 may be perfectly normal on a view camera, but will cause a noticeable loss in sharpness on a FF 35mm. Personally, since I’ve tested my lenses and know the effect on acuity, I try not to go beyond f11 on a FF and f8 on a crop body unless I’m shooting Macros or DOF is really critical. Here are example acuity curves of a FF lens, and the effect of diffraction at smaller apertures is obvious.

photoman43

I agree that you need to do your own testing with each lens and camera body separately. Results can be unique to each shooting situation too. With my Nikon 200 mm f4 macro lens on my D 850, at 1 :1, I try not to use an aperture opening smaller than f 8 as IQ degrades at f 11, f 16 and f 22. But at f 36 it does not appear to be that bad. There are Diffraction Limit Calculators on the Internet. Check them out for your lens, body and f stop. But then do your own tests.

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And put the results in spread sheets just like you always do ?

Picture Taker Loc: Michigan Thumb

as "CHG CANON" points out it depends. At f22 you are opening the door to picture quality and should be to the middle f stops for best lens quality. But as "CHG CANON" points out the situation is a setting changer. Too dark , too light 10mm or 500mm situations is what calls the shots. Also can be quality of the lens, capabilities.

User ID

So some of us now and then shoot at or very near to wide open, by necessity. We tolerate a certain loss in IQ to get that shutter speed or to avoid extended ISO. It’s not ideal but it’s a well balanced compromise.

If you truly need more DoF than you get at f:11 then you’re simply faced with negotiating yet another well balanced compromise ... shoot F:16 to f:32 as needed and get the intended image.

Maybe certain ultra mega geeks shoot EVERYTHING between f:4.5 and f:9.5. They may have some useful knowledge to share but it’s not likely that their pix will bring us to places or experiences we had never imagined :-\

wdross Loc: Castle Rock, Colorado

Yes, diffraction does affect the image quality as far as sharpness. But if I have to shoot f11 (diffraction occurs at lower f-stops with 4/3rds) or beyond to get the shot, I do that. It is something one does their best to avoid if they can. From proper viewing distances the loss of sharpness is not that noticeable and some sharpening can be gained back in PP.