jradose wrote:
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?
I have read numerous articles about diffraction. I... (
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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.