Macro Diffraction
Calculate effective aperture and diffraction in macro photography
Calculate effective aperture and diffraction in macro photography
Marked Aperture
f/8
Effective Aperture
f/16
Status
Diffraction Limited
Light Loss
2 stops
Airy Disk
21.47 µm
Pixel Pitch
6 µm
Max Aperture for Sharpness
f/2.2
Optimal Aperture Range
For best results at 1:1 magnification, use marked apertures between f/2.8 and f/2.2.
Analysis
Effective Aperture Reference Table
| Marked | 1:4 (0.25×) | 1:2 (0.5×) | 1:1 (1×) | 2:1 (2×) | 3:1 (3×) | 5:1 (5×) |
|---|---|---|---|---|---|---|
| f/2.8 | f/3.5 | f/4.2 | f/5.6 | f/8.4 | f/11.2 | f/16.8 |
| f/4 | f/5 | f/6 | f/8 | f/12 | f/16 | f/24 |
| f/5.6 | f/7 | f/8.4 | f/11.2 | f/16.8 | f/22.4 | f/33.6 |
| f/8 | f/10 | f/12 | f/16 | f/24 | f/32 | f/48 |
| f/11 | f/13.8 | f/16.5 | f/22 | f/33 | f/44 | f/66 |
| f/16 | f/20 | f/24 | f/32 | f/48 | f/64 | f/96 |
Red values indicate severe diffraction softening (effective aperture > f/22).
Effective Aperture at Different Magnifications
Vertical line = f/22. Bars exceeding this indicate severe diffraction.
Light Loss by Magnification
Increase ISO or exposure time to compensate for light loss.
Macro Diffraction Formulas
Effective Aperture: N_eff = N × (1 + m)
Airy Disk: d = 2.44 × λ × N_eff
Light Loss: stops = 2 × log₂(1 + m)
Where: