Lens Diffraction and Its Practical Application to Photography

Nature photographer Steve Perry has released a new 14-minute video educating his audience all about lens diffraction. Beginning with a somewhat technical explanation of how diffraction occurs with your lenses, the video quickly moves into giving practical answers and examples for questions that you may have wondered when it comes to choosing f-stops and how to get the sharpest possible image.

As Perry points out, diffraction is “actually a property of physics, not a defect in manufacturing.” As a photographer, it is simply something that you must learn to work with regardless of lens choice, and this video gives you all the information you’ll need to make smart decisions when shooting for top-quality images.

Diffraction increases as you stop down your aperture

Here are some of the questions answered in this video:

  • “Wait a minute, I thought when I stopped the lens down to a smaller f-stop that I would have more in focus. Is that not true?” (4:05)
  • “OK, if I get more diffraction as I stop down, why is my lens sharper when I stop it down a notch or two from wide open?” (5:05)
  • “So, does this mean I should never shoot small f-stops - just stick with the sweet spot or at least f/8 and faster?” (6:05)
  • “I hear that higher resolution cameras show the effects of diffraction much sooner than lower resolution cameras. Does that mean that I shouldn’t upgrade to a higher resolution camera?” (7:05)
  • “Can I just sharpen out diffraction?” (10:55)
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3 Comments

Bill Blount's picture

Excellent video!

f8 and be there. That familiar phrase has persisted for good reasons.

Shane Castle's picture

An good a summary of the diffraction issue in photography as I have seen. He makes clear that it's a tradeoff between DoF and overall sharpness. He also touches on the "printability" of the resulting images, but I think he should have emphasized that unless you are using a loupe on a print off one of the best professional printers you are not likely to see any appreciable difference. It all depends on what your goals are. If you are doing rostrum work and photographing documents or artwork, you must pay attention to diffraction in your lenses. For landscapes and other "real world" photography, maybe not so much.

Rob Watts's picture

Great video. I've been wondering this a lot myself lately when watching videos or reading tutorials and some of the pros are shooting f/22 or f/32 on a lens I happen to know goes to crap after about f/10. I'm still not clear on why someone would give up their sharpness like that, especially when newer techniques such as stacking exist (less work maybe?)