Sony α7R IV Diffraction Limit
With a 720 nm infrared filter, the Sony α7R IV stays free of visible diffraction up to ƒ/4.5, and diffraction starts to soften images at ƒ/7.1. Unconverted (hot mirror), it is diffraction-free up to ƒ/6.3 and soft from ƒ/10.1. These limits come from its 3.76 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 IV in the calculator
Sony α7R IV specifications
- Pixel pitch: 3.76 μm
- Megapixels: 61.0
- Pixels: 9504 × 6336
- Sensor: Full Frame, 35.7 × 23.8 mm
Buy the Sony α7R IV: 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/4.5 | ƒ/5.6 | ƒ/7.1 |
| Hot mirror or UV/IR cut | ƒ/6.3 | ƒ/8 | ƒ/10.1 |
| 470 nm high-pass | ƒ/4.5 | ƒ/5.6 | ƒ/7.1 |
| 550 nm high-pass | ƒ/4.5 | ƒ/5.6 | ƒ/7.1 |
| 590 nm high-pass | ƒ/4.5 | ƒ/5.6 | ƒ/7.1 |
| 665 nm high-pass | ƒ/4.5 | ƒ/5.6 | ƒ/7.1 |
| 720 nm high-pass | ƒ/4.5 | ƒ/5.6 | ƒ/7.1 |
| 780 nm high-pass | ƒ/4.5 | ƒ/5.6 | ƒ/7.1 |
| 830 nm high-pass | ƒ/4.5 | ƒ/5.6 | ƒ/7.1 |
| 930 nm high-pass | ƒ/4.5 | ƒ/5.6 | ƒ/7.1 |
| 1000 nm high-pass | ƒ/4.5 | ƒ/5.6 | ƒ/7.1 |
| IR Chrome | ƒ/4.5 | ƒ/5.6 | ƒ/7.1 |
| UV Bandpass | ƒ/11 | ƒ/14.3 | ƒ/18 |
Diffraction ratio at each ƒ-stop
The Airy disk diameter divided by the 3.76 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 | 0.32 | 0.36 | 0.43 | 0.5 | 0.54 | 0.6 | 0.65 | 0.71 | 0.75 | 0.84 | 0.91 |
| ƒ/2 | 0.45 | 0.52 | 0.61 | 0.71 | 0.77 | 0.86 | 0.93 | 1.01 | 1.08 | 1.21 | 1.3 |
| ƒ/2.8 | 0.64 | 0.73 | 0.85 | 1 | 1.07 | 1.21 | 1.31 | 1.42 | 1.51 | 1.69 | 1.82 |
| ƒ/4 | 0.91 | 1.04 | 1.22 | 1.43 | 1.53 | 1.73 | 1.87 | 2.02 | 2.15 | 2.41 | 2.6 |
| ƒ/5.6 | 1.27 | 1.45 | 1.71 | 2 | 2.14 | 2.42 | 2.62 | 2.83 | 3.02 | 3.38 | 3.63 |
| ƒ/8 | 1.82 | 2.08 | 2.44 | 2.86 | 3.06 | 3.45 | 3.74 | 4.05 | 4.31 | 4.83 | 5.19 |
| ƒ/11 | 2.5 | 2.86 | 3.36 | 3.93 | 4.21 | 4.75 | 5.14 | 5.57 | 5.92 | 6.64 | 7.14 |
| ƒ/16 | 3.63 | 4.15 | 4.88 | 5.71 | 6.13 | 6.9 | 7.48 | 8.1 | 8.62 | 9.66 | 10.38 |
| ƒ/22 | 5 | 5.71 | 6.71 | 7.85 | 8.42 | 9.49 | 10.28 | 11.14 | 11.85 | 13.28 | 14.28 |
| ƒ/32 | 7.27 | 8.31 | 9.76 | 11.42 | 12.25 | 13.81 | 14.95 | 16.2 | 17.24 | 19.31 | 20.77 |
| 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 IV. The same pixel pitch gives the same diffraction limits.
- Sony α7CR (3.76 μm)
- Sony α7R V (3.76 μm)
- Leica M11 (3.78 μm)
- Leica Q3 (3.78 μm)
- Leica SL3 (3.78 μm)
- Sony α7R VI (3.60 μm)
Pixel pitch comes from the camera database. Send a correction if anything here is wrong.