Lenses & focus / Learn by doing
Diffraction explained simply
What is “Diffraction”?
The spreading of light as it passes through a small opening. At very small apertures it can reduce fine image detail.
- 01Smaller opening
- 02Light spreads
- 03Fine detail softens
How do you use Diffraction practically?
A small exercise
Photograph a detailed still object at f/8 and f/22, compensating exposure and keeping focus steady. Compare fine textures.
- Make a starting version and keep it so you can compare fairly.
- Try the change in the exercise. Keep unrelated choices steady where the exercise allows.
- Compare the result at the size your viewer will actually see. Write down what changed and whether it helped.
How does Diffraction solve a problem?
It helps explain why closing the aperture as far as possible can make a whole photograph look less crisp.
What can go wrong?
The best aperture depends on the needed depth of field. Some diffraction may be a sensible trade-off.
How do you turn the idea into a useful solution?
Start with the specific problem in your image or brief, try the exercise, and keep the version that meets that need. If the result is worse, return to the starting version and change one choice at a time.
Quick check: can you explain the three ideas in the diagram?
Smaller opening → Light spreads → Fine detail softens. Explain how each relates to the exercise. Then compare the starting version with your result and choose the one that meets your brief.
Related video lesson
Lens basics — Canon
This related lesson gives wider context for the topic. Camera menus and software versions may differ from yours.
Loading the player connects to YouTube. You can also watch the lesson on YouTube.Keep exploring
Try the idea in a studio shoot
Planning a portrait or product session? Use the glossary with our practical shoot guides, then check the studio facilities and send your confirmed requirements with an availability enquiry.