aChanceEncounter
Senior Member
Been fine tuning this brief article with ChatGPT over the last couple days to include questions and perspectives I have wondered about regarding diffraction. Interested in your thoughts?
When you stop down a lens to achieve more depth of field, you’re also introducing a fundamental optical effect called diffraction. This is not a flaw in your lens – it’s a property of light itself.
What is Diffraction?
Diffraction happens when light waves bend as they pass through a small aperture. The smaller the opening (higher f‑stop), the more light spreads out, creating a larger blur circle called the Airy disk. Even the sharpest lens can’t overcome this – it’s basic physics.
How Sensor Pixel Size Comes Into Play
The smaller the pixel pitch (distance between pixels), the more that diffraction blur affects the image. High‑resolution sensors with tiny pixels will show diffraction softening earlier than lower‑resolution sensors.
Pixel pitch and diffraction thresholds for Fujifilm X‑series bodies:
Camera ModelResolutionPixel Pitch (approx.)
Diffraction Noticeable
X‑T5 / X‑H240 MP~3.03 µmf/5.6–f/8
X‑T4 / X‑T3 / X‑H2S26 MP~3.74 µmf/8–f/11
X‑T2 24 MP~3.92 µmf/8–f/11
X‑T116 MP~4.76 µmf/11–f/13
Cameras with larger pixels (like the X‑T1) can be stopped down further before diffraction visibly softens fine detail. Higher‑resolution models like the X‑T5 produce more detail overall but reveal diffraction earlier.
The DOF vs. Diffraction Trade‑Off
Stopping down increases depth of field, which brings more of the scene into focus. But the trade‑off is reduced fine detail from diffraction blur. For critical landscape work, many photographers aim for a sweet spot aperture (f/4–f/8 on high‑MP APS‑C) where sharpness and DOF balance out. For extreme DOF without diffraction softening, focus stacking is the best solution.
Do Primes Control Diffraction Better Than Zooms?
Diffraction is caused by physics and is not dependent on lens type. A prime lens cannot delay when diffraction begins. However, primes often have higher optical quality and start out sharper than zooms. Because of this, images from primes can look crisper at small apertures even though the diffraction effect is exactly the same. Zoom lenses, especially variable‑aperture designs, may already be a bit softer, so diffraction’s impact can seem more noticeable.
Screen vs. Print – Why It Looks Different
When you view images at 100% on a high‑resolution monitor, any loss of micro‑contrast from diffraction is obvious. But prints are seen at lower resolution (usually 200–300 dpi) and at greater viewing distances. As a result:
Takeaways for Photographers
When you stop down a lens to achieve more depth of field, you’re also introducing a fundamental optical effect called diffraction. This is not a flaw in your lens – it’s a property of light itself.
What is Diffraction?Diffraction happens when light waves bend as they pass through a small aperture. The smaller the opening (higher f‑stop), the more light spreads out, creating a larger blur circle called the Airy disk. Even the sharpest lens can’t overcome this – it’s basic physics.
How Sensor Pixel Size Comes Into PlayThe smaller the pixel pitch (distance between pixels), the more that diffraction blur affects the image. High‑resolution sensors with tiny pixels will show diffraction softening earlier than lower‑resolution sensors.
Pixel pitch and diffraction thresholds for Fujifilm X‑series bodies:
Camera ModelResolutionPixel Pitch (approx.)
Diffraction Noticeable
X‑T5 / X‑H240 MP~3.03 µmf/5.6–f/8
X‑T4 / X‑T3 / X‑H2S26 MP~3.74 µmf/8–f/11
X‑T2 24 MP~3.92 µmf/8–f/11
X‑T116 MP~4.76 µmf/11–f/13
Cameras with larger pixels (like the X‑T1) can be stopped down further before diffraction visibly softens fine detail. Higher‑resolution models like the X‑T5 produce more detail overall but reveal diffraction earlier.
The DOF vs. Diffraction Trade‑OffStopping down increases depth of field, which brings more of the scene into focus. But the trade‑off is reduced fine detail from diffraction blur. For critical landscape work, many photographers aim for a sweet spot aperture (f/4–f/8 on high‑MP APS‑C) where sharpness and DOF balance out. For extreme DOF without diffraction softening, focus stacking is the best solution.
Do Primes Control Diffraction Better Than Zooms?Diffraction is caused by physics and is not dependent on lens type. A prime lens cannot delay when diffraction begins. However, primes often have higher optical quality and start out sharper than zooms. Because of this, images from primes can look crisper at small apertures even though the diffraction effect is exactly the same. Zoom lenses, especially variable‑aperture designs, may already be a bit softer, so diffraction’s impact can seem more noticeable.
Screen vs. Print – Why It Looks DifferentWhen you view images at 100% on a high‑resolution monitor, any loss of micro‑contrast from diffraction is obvious. But prints are seen at lower resolution (usually 200–300 dpi) and at greater viewing distances. As a result:
- Mild diffraction at f/8–f/11 is rarely visible in print, even at large sizes.
- The “softness” you see when zoomed in disappears when the image is downsampled for printing.
Takeaways for Photographers- Diffraction is unavoidable – it’s a law of physics.
- Cameras with larger pixels (X‑T1, X‑T2) are more forgiving at small apertures.
- High‑resolution cameras like X‑T5 reveal diffraction earlier but provide more detail overall.
- Use f/4–f/8 for maximum sharpness on high‑MP APS‑C sensors.
- With proper post‑processing, f/11 or even f/13 shots can still produce sharp, detailed prints.
- Primes don’t change diffraction physics, but because they are usually sharper, they can still produce better small‑aperture images than zooms.
- For large DOF without losing detail, consider focus stacking when possible.
- Don’t panic about mild diffraction – prints hide it much better than screens.
