Sony α7 III Diffraction Limit
With a 720 nm infrared filter, the Sony α7 III stays free of visible diffraction up to ƒ/7.1, and diffraction starts to soften images at ƒ/11. Unconverted (hot mirror), it is diffraction-free up to ƒ/10.1 and soft from ƒ/16. These limits come from its 5.93 μm pixel pitch: longer infrared wavelengths make a larger Airy disk, so diffraction appears at wider apertures than in visible light.
Open the Sony α7 III in the calculator
Sony α7 III specifications
- Pixel pitch: 5.93 μm
- Megapixels: 24.2
- Pixels: 6000 × 4000
- Sensor: Full Frame, 35.6 × 23.8 mm
Buy the Sony α7 III: KEH Adorama B&H
Sharpest ƒ-stop by filter
Safe is the narrowest aperture with a diffraction ratio of 3 or lower at every wavelength the filter passes. Caution allows up to 3.75. Avoid is the first aperture where any wavelength reaches 4.5. All three are calculated to the one-third stop. See which wavelengths each filter passes.
| Filter | Safe | Caution | Avoid |
|---|---|---|---|
| Full spectrum | ƒ/7.1 | ƒ/9 | ƒ/11 |
| Hot mirror or UV/IR cut | ƒ/10.1 | ƒ/11 | ƒ/16 |
| 470 nm high-pass | ƒ/7.1 | ƒ/9 | ƒ/11 |
| 550 nm high-pass | ƒ/7.1 | ƒ/9 | ƒ/11 |
| 590 nm high-pass | ƒ/7.1 | ƒ/9 | ƒ/11 |
| 665 nm high-pass | ƒ/7.1 | ƒ/9 | ƒ/11 |
| 720 nm high-pass | ƒ/7.1 | ƒ/9 | ƒ/11 |
| 780 nm high-pass | ƒ/7.1 | ƒ/9 | ƒ/11 |
| 830 nm high-pass | ƒ/7.1 | ƒ/9 | ƒ/11 |
| 930 nm high-pass | ƒ/7.1 | ƒ/9 | ƒ/11 |
| 1000 nm high-pass | ƒ/7.1 | ƒ/9 | ƒ/11 |
| IR Chrome | ƒ/7.1 | ƒ/9 | ƒ/11 |
| UV Bandpass | ƒ/18 | ƒ/22 | ƒ/28.5 |
Diffraction ratio at each ƒ-stop
The Airy disk diameter divided by the 5.93 μm pixel pitch, for every wavelength from ultraviolet to infrared. A filter only passes some of these wavelengths; the table above applies each filter’s set. How the ratio is calculated.
| ƒ-stop | 350 nm | 400 nm | 470 nm | 550 nm | 590 nm | 665 nm | 720 nm | 780 nm | 830 nm | 930 nm | 1000 nm |
|---|---|---|---|---|---|---|---|---|---|---|---|
| ƒ/1.4 | 0.2 | 0.23 | 0.27 | 0.32 | 0.34 | 0.38 | 0.41 | 0.45 | 0.48 | 0.54 | 0.58 |
| ƒ/2 | 0.29 | 0.33 | 0.39 | 0.45 | 0.49 | 0.55 | 0.59 | 0.64 | 0.68 | 0.77 | 0.82 |
| ƒ/2.8 | 0.4 | 0.46 | 0.54 | 0.63 | 0.68 | 0.77 | 0.83 | 0.9 | 0.96 | 1.07 | 1.15 |
| ƒ/4 | 0.58 | 0.66 | 0.77 | 0.91 | 0.97 | 1.09 | 1.19 | 1.28 | 1.37 | 1.53 | 1.65 |
| ƒ/5.6 | 0.81 | 0.92 | 1.08 | 1.27 | 1.36 | 1.53 | 1.66 | 1.8 | 1.91 | 2.14 | 2.3 |
| ƒ/8 | 1.15 | 1.32 | 1.55 | 1.81 | 1.94 | 2.19 | 2.37 | 2.57 | 2.73 | 3.06 | 3.29 |
| ƒ/11 | 1.58 | 1.81 | 2.13 | 2.49 | 2.67 | 3.01 | 3.26 | 3.53 | 3.76 | 4.21 | 4.53 |
| ƒ/16 | 2.3 | 2.63 | 3.09 | 3.62 | 3.88 | 4.38 | 4.74 | 5.14 | 5.46 | 6.12 | 6.58 |
| ƒ/22 | 3.17 | 3.62 | 4.25 | 4.98 | 5.34 | 6.02 | 6.52 | 7.06 | 7.51 | 8.42 | 9.05 |
| ƒ/32 | 4.61 | 5.27 | 6.19 | 7.24 | 7.77 | 8.76 | 9.48 | 10.27 | 10.93 | 12.25 | 13.17 |
| No visible diffraction (less than 3) | |
| Visible diffraction may slightly impact image sharpness (3 to 4.5) | |
| Visible diffraction will impact image sharpness (4.5 or greater) |
Cameras with similar pixel pitch
Other Full Frame cameras within 0.2 μm of the Sony α7 III. The same pixel pitch gives the same diffraction limits.
- Leica SL2-S (5.93 μm)
- Panasonic Lumix DC-S5 (5.93 μm)
- Panasonic Lumix DC-S5 II (5.93 μm)
- Sony α7C (5.93 μm)
- Sony α9 (5.93 μm)
- Sony α9 II (5.93 μm)
Pixel pitch comes from the camera database. Send a correction if anything here is wrong.