Sony α7R III Diffraction Limit
With a 720 nm infrared filter, the Sony α7R III stays free of visible diffraction up to ƒ/5, and diffraction starts to soften images at ƒ/9. Unconverted (hot mirror), it is diffraction-free up to ƒ/7.1 and soft from ƒ/12.7. These limits come from its 4.52 μm pixel pitch: longer infrared wavelengths make a larger Airy disk, so diffraction appears at wider apertures than in visible light.
Open the Sony α7R III in the calculator
Sony α7R III specifications
- Pixel pitch: 4.52 μm
- Megapixels: 42.4
- Pixels: 7952 × 5304
- Sensor: Full Frame, 35.9 × 24.0 mm
Buy the Sony α7R 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/5 | ƒ/6.3 | ƒ/9 |
| Hot mirror or UV/IR cut | ƒ/7.1 | ƒ/9 | ƒ/12.7 |
| 470 nm high-pass | ƒ/5 | ƒ/6.3 | ƒ/9 |
| 550 nm high-pass | ƒ/5 | ƒ/6.3 | ƒ/9 |
| 590 nm high-pass | ƒ/5 | ƒ/6.3 | ƒ/9 |
| 665 nm high-pass | ƒ/5 | ƒ/6.3 | ƒ/9 |
| 720 nm high-pass | ƒ/5 | ƒ/6.3 | ƒ/9 |
| 780 nm high-pass | ƒ/5 | ƒ/6.3 | ƒ/9 |
| 830 nm high-pass | ƒ/5 | ƒ/6.3 | ƒ/9 |
| 930 nm high-pass | ƒ/5 | ƒ/6.3 | ƒ/9 |
| 1000 nm high-pass | ƒ/5 | ƒ/6.3 | ƒ/9 |
| IR Chrome | ƒ/5 | ƒ/6.3 | ƒ/9 |
| UV Bandpass | ƒ/12.7 | ƒ/16 | ƒ/22 |
Diffraction ratio at each ƒ-stop
The Airy disk diameter divided by the 4.52 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 | 0.26 | 0.3 | 0.36 | 0.42 | 0.45 | 0.5 | 0.54 | 0.59 | 0.63 | 0.7 | 0.76 |
| ƒ/2 | 0.38 | 0.43 | 0.51 | 0.59 | 0.64 | 0.72 | 0.78 | 0.84 | 0.9 | 1 | 1.08 |
| ƒ/2.8 | 0.53 | 0.6 | 0.71 | 0.83 | 0.89 | 1.01 | 1.09 | 1.18 | 1.25 | 1.41 | 1.51 |
| ƒ/4 | 0.76 | 0.86 | 1.01 | 1.19 | 1.27 | 1.44 | 1.55 | 1.68 | 1.79 | 2.01 | 2.16 |
| ƒ/5.6 | 1.06 | 1.21 | 1.42 | 1.66 | 1.78 | 2.01 | 2.18 | 2.36 | 2.51 | 2.81 | 3.02 |
| ƒ/8 | 1.51 | 1.73 | 2.03 | 2.38 | 2.55 | 2.87 | 3.11 | 3.37 | 3.58 | 4.02 | 4.32 |
| ƒ/11 | 2.08 | 2.38 | 2.79 | 3.27 | 3.5 | 3.95 | 4.28 | 4.63 | 4.93 | 5.52 | 5.94 |
| ƒ/16 | 3.02 | 3.45 | 4.06 | 4.75 | 5.1 | 5.74 | 6.22 | 6.74 | 7.17 | 8.03 | 8.64 |
| ƒ/22 | 4.16 | 4.75 | 5.58 | 6.53 | 7.01 | 7.9 | 8.55 | 9.26 | 9.86 | 11.04 | 11.88 |
| ƒ/32 | 6.05 | 6.91 | 8.12 | 9.5 | 10.19 | 11.49 | 12.44 | 13.47 | 14.34 | 16.07 | 17.27 |
| 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 α7R III. The same pixel pitch gives the same diffraction limits.
- Sony α7R II (4.50 μm)
- Leica M10-R (4.58 μm)
- Canon EOS R5 (4.40 μm)
- Panasonic Lumix DC-S1R II (4.40 μm)
- Canon EOS R5 C (4.39 μm)
- Canon EOS R5 Mark II (4.39 μm)
Pixel pitch comes from the camera database. Send a correction if anything here is wrong.