leftyD500 Loc: Ocala, Florida

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?

rmalarz Loc: Tempe, Arizona

I tend to agree and ignore the diffraction statement. f/22 on one lens is not the same aperture as f/22 on another. So, how does some magic f-number come into play?
--Bob

Architect1776 Loc: In my mind

R.G. Loc: Scotland

The size of the photosites (sensor pixels) is a factor. With a high resolution sensor the diffraction caused at, say, f/16 will be more significant than it would be with a lower resolution sensor. Diffraction would have to be extreme before it caused what you would describe as a loss of detail. More typically it causes softening of edges, which can be mitigated (up to a point) with the right sort of sharpening.

bleirer

Sure it is a problem, but the effect is gradual and different if you are viewing at 100% vs. Printing an 8x10. I like this calculator because you get to see both options. All you can do is keep it in mind when setting the aperture and know that at some point more depth of field is fighting against softening due to diffraction.

https://www.photopills.com/calculators/diffraction

Longshadow Loc: Audubon, PA, United States

Some people are too persnickety?

(If it works (looks good), ship it.)

I'll use whatever my lens will do, depending on the effect I desire.

CHG_CANON Loc: the Windy City

Although many will say don't go smaller than f/16, the more accurate statement is that you perform your own testing with your specific camera model (sensor size) and your specific lenses. You should be able to discern the overall softening of details when shooting the exact same subject as you walk the aperture from the max width to the minimum opening. Just set-up a tripod and shoot in aperture priority letting the camera maintain the same exposure. Look at the images at the 1:1 pixel-level detail, especially in the background where you're supposedly capturing more depth of field. You should note the depth of field does not increase where the sharpness does visually soften. Make note of that cross-over point for each lens tested.

The last time I looked at this question with my 180L macro, I was looking at flowers and it was clear beyond f/18 the image just got worse, even where sharply focused in earlier / wider apertures. You can do the same with your preferred landscape lens. You don't have to go anywhere special, just shoot down your own street. A tip I learned was to tilt the camera at a 45 degree angle so that a corner of your frame (either the 'lower' or 'upper') intersects with the horizon line. Then, as you walk the images 1 by 1 at the pixel level details, the diminished returns of the smaller apertures become easier to see on your large screen display as you inspect the corners / background details.

flyboy61 Loc: The Great American Desert

There are many convinced advocates on either side of the question, but for me, Bryan Peterson addressed the subject very well in both of his books" Understanding Exposure" eds. #3 and 4. As far as I am concerned, it is a non-issue, like the other "hot topics"...Bokeh, shooting wide open, the holiness of f/1.4,and Hyperfocal Distance! f/stops...if you got 'em USE them, conditions necessitating!

Bill_de Loc: US

You answered your own question here. It's magic!

---

DirtFarmer Loc: Escaped from the NYC area, back to MA

(Download)

larryepage Loc: North Texas area

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.

Charles 46277 Loc: Fulton County, KY

I would say for a start that magnification is the issue. Smaller apertures do indeed introduce diffraction, which means lines are less sharp; but this is more noticeable the greater the image is enlarged after shooting. That is why diffraction was not an issue with wide angle lenses on large format film, or medium format digital sensors, if the image is not enlarged much. The bigger the format of film, the smaller permissible apertures, so anything above 4x5 film can easily get good results at f64 or even more, though everyday lenses will not stop down usually past f32. This is because the diffraction in an 8x10 or 5x7 negative is not regularly enlarged enough to show. The photographer has to know how soft the images can be for the desired result--the increased depth of field of small stops may be more important than the fine hairs on a coat or an animal, and the photographer must consider how much the picture must be (or can be) enlarged.

Many people with digital cameras fret seriously about diffraction, because their sensors are very small, and cannot take the focus diffraction on many pictures when enlarged a lot. On the other hand, pictures for a family vacation album will not notice diffraction, but will definitely suffer from shallow depth of field.

A common rule with 4x5 cameras was f22 as a starting point for scenic views (more if needed), or f8 for photojournalism, where a person is the typical subject and action is an issue. So the diffraction affect will also depend on the style or category of subjects. If you can get the elements you want sharp in more or less a flat line, large apertures will allow great enlargement without diffraction setting in. They will also allow faster shutter speeds, so... Also, if whatever you want sharp is farther away, you can use larger apertures with good depth of field.

F16 should be brilliant for most general photography--you move up or down according to the light and the result you want in the picture. Today, many people think only one thing in a picture should be sharp, so they use wide apertures on principle. The size of the final picture is usually never considered while shooting--but it is certainly a consideration for how to shoot.

Manufacturers put more apertures on a lens--to the point they believe the result is not good enough. I like lenses that give me the choice of a small aperture. I think the Rex Begonia in my photo avatar here above was shot on a Canon 650D (cropped sensor) at f32 using a large format lens (Schneider Xenar 360mm lens for 11x14 camera). I probably would not enlarge it beyond 11x14.

Strodav Loc: Houston, Tx

Just try it for yourself. In my case, I was reading one of Bryan Peterson's books where he advocates small apertures for large DOF, so I tried it on a landscape using a DX body and wider angle lens. Tripod, remote release, ... I started at f/4 then started moving up to f/22. I pulled them up in Lightroom and guess what, they started to get softer after about f/11 even tough DOF got larger as expected. At the time I couldn't figure out why, started to do a little research and sure enough, diffraction kept coming up as the reason.

So now I usually take 3, maybe more, landscape shots focusing close, medium, and far then focus stack in PS. That gives me the DOF I'm looking for while avoiding diffraction.

Again, try it for yourself.

User ID

You’ve read articles about diffraction ? Forget them. Ignore them. And ignore anything else those authors write. You don’t want advice (about anything) from the sort of folks who’ll write articles about diffraction. Period.


You can choose any aperture from f:8 to f:128 as your diffraction limit. The only meaningful parameter is how anal you are about IQ. IOW no one can set that limit for you nor can anyone advise you *how* to judge your images when testing to choose a limit.


That said, expect plenty of self declared experts to offer guidance and rules of thumb. Try not to think about where those thumbs have been. Be kind (like I am not). They can’t help themselves. Listen to the many users who don’t worry about it.

User ID

Always the voice in the wilderness. A fine honest try, anywho.