I have read numerous articles about diffraction. I have watched numerous videos about diffraction. I still have mixed thoughts about just how much of a problem it really is, and what, if anything, can be done if it is a problem. Some authors of articles and/or videos say diffraction takes a toll on image quality, and they suggest you don't shoot narrower than an F/16 aperture. Others, have a differing view. I will cite Bryan Peterson (I love his "You Keep Shooting" videos) constantly suggests shooting at F/22 (or higher if your camera allows). So, asking fellow Hoggers, what is your take on diffraction.....a problem to be concerned with, or no discernable problem, shoot F/22 for more DOF?

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.

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.

Diffraction is a real thing, just like barrel distortion, pincushion distortion, chromatic aberration, chromatic aberration, volume anamorphosis, and a whole additional list of other "undesirable alterations" to your image are real things. In fact there are at least two forms of diffraction, namely single edge diffraction and the sort of interference diffraction that arises when light passes through a hole in something, like a slit or a pinhole. The thing is, the geometry of diffraction is inversely related to the wavelength of the light being diffracted, and since the wavelength of visible red light is almost twice the wavelength of visible violet light, the effects of those two colors is not seen anywhere close to the same place. Also, since the wavelength of light is so short, the distances over which diffraction redirects light are generally very small, unless the light is very intense and very monochromatic. If it is also coherent (parallel and in phase, like the light from a laser, in addition to being monochromatic), it is very visible, very understandable, and just generally very impressive.

But like all those other distortions, diffraction in real life may or may not be a problem. If it is a problem, it may or may not be a big problem. So the answer is that if you think it is a "thing," you need to somehow set up and test to see if it is a problem for you or not. And you need to think about your testing and your results . If you see a problem at small apertures, does it come from the aperture, or does it come from the high ISO you have selected to allow you to use that tiny aperture. And if it is a problem, is it just something that you can see under extreme magnification and focused inspection, or is it something that really affects the quality or character (or both) of your final result. And is it a general problem that occurs every time and every where, or does it occur only with a specific combination of circumstances. Can you identify those, so that you can avoid get into the situations where it occurs and not worry about it otherwise?

To me, all of this is simply understanding the technical aspects and potential limitations of the craft of photography. Once that is done, the problems can either be avoided or perhaps even embraced. As an example, I spent quite a bit of time and energy trying to get rid of the infrared noise that creates the horizon glow in my night sky photographs. Then I realized that besides being a natural phenomenon arising from the ground having been heated during the day, the glow is actually beneficial...it helps define the boundary between the sky and the earth. I still edit it some to control its extent, but it no longer keeps me awake at night when I can't get rid of it.

With the effects of diffraction, there may be a tradeoff between overall sharpness and localized depth of field. That's really a reasonable negotiation to have to make, if you think about it. So try to let it be fun, not bring frustration.

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

I have read numerous articles about diffraction. I have watched numerous videos about diffraction. I still have mixed thoughts about just how much of a problem it really is, and what, if anything, can be done if it is a problem. Some authors of articles and/or videos say diffraction takes a toll on image quality, and they suggest you don't shoot narrower than an F/16 aperture. Others, have a differing view. I will cite Bryan Peterson (I love his "You Keep Shooting" videos) constantly suggests shooting at F/22 (or higher if your camera allows). So, asking fellow Hoggers, what is your take on diffraction.....a problem to be concerned with, or no discernable problem, shoot F/22 for more DOF?

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

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.

Diffraction is one of the many physical laws of light. When light passes through an orifice (an aperture) the wave of rays which are coming in parallel fan out. Think of this as how a stone dropped into a pool of water create the ripple (by the way, water and light have a lot in common in physics).

Because these rays are now more sprayed than laminar when they hit the sensor the pixels sense an overlap which creates a softer image and artifacts on fine edges such as hairs on the subject.

The amount of magnification of a lens, or how it is extended to create a higher magnification, causes an "effective aperture" which can be far and away different than the f/stop setting on the lens or shown in the camera display.

I shoot macro and extreme macro on a near daily basis and diffraction is always an issue to contend with. Attached is a chart that I put together that is used as a guide to help avoid the effect of diffraction caused by the "effective f/stop"