Canon EOS RP Diffraction Limit
With a 720 nm infrared filter, the Canon EOS RP stays free of visible diffraction up to ƒ/6.3, and diffraction starts to soften images at ƒ/11. Unconverted (hot mirror), it is diffraction-free up to ƒ/9 and soft from ƒ/16. These limits come from its 5.75 μm pixel pitch: longer infrared wavelengths make a larger Airy disk, so diffraction appears at wider apertures than in visible light.
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Canon EOS RP specifications
- Pixel pitch: 5.75 μm
- Megapixels: 26.2
- Pixels: 6240 × 4160
- Sensor: Full Frame, 35.9 × 24.0 mm
Buy the Canon EOS RP: 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/6.3 | ƒ/8 | ƒ/11 |
| Hot mirror or UV/IR cut | ƒ/9 | ƒ/11 | ƒ/16 |
| 470 nm high-pass | ƒ/6.3 | ƒ/8 | ƒ/11 |
| 550 nm high-pass | ƒ/6.3 | ƒ/8 | ƒ/11 |
| 590 nm high-pass | ƒ/6.3 | ƒ/8 | ƒ/11 |
| 665 nm high-pass | ƒ/6.3 | ƒ/8 | ƒ/11 |
| 720 nm high-pass | ƒ/6.3 | ƒ/8 | ƒ/11 |
| 780 nm high-pass | ƒ/6.3 | ƒ/8 | ƒ/11 |
| 830 nm high-pass | ƒ/6.3 | ƒ/8 | ƒ/11 |
| 930 nm high-pass | ƒ/6.3 | ƒ/8 | ƒ/11 |
| 1000 nm high-pass | ƒ/6.3 | ƒ/8 | ƒ/11 |
| IR Chrome | ƒ/6.3 | ƒ/8 | ƒ/11 |
| UV Bandpass | ƒ/16 | ƒ/22 | ƒ/28.5 |
Diffraction ratio at each ƒ-stop
The Airy disk diameter divided by the 5.75 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 | 0.21 | 0.24 | 0.28 | 0.33 | 0.35 | 0.4 | 0.43 | 0.46 | 0.49 | 0.55 | 0.59 |
| ƒ/2 | 0.3 | 0.34 | 0.4 | 0.47 | 0.5 | 0.56 | 0.61 | 0.66 | 0.7 | 0.79 | 0.85 |
| ƒ/2.8 | 0.42 | 0.48 | 0.56 | 0.65 | 0.7 | 0.79 | 0.86 | 0.93 | 0.99 | 1.11 | 1.19 |
| ƒ/4 | 0.59 | 0.68 | 0.8 | 0.93 | 1 | 1.13 | 1.22 | 1.32 | 1.41 | 1.58 | 1.7 |
| ƒ/5.6 | 0.83 | 0.95 | 1.12 | 1.31 | 1.4 | 1.58 | 1.71 | 1.85 | 1.97 | 2.21 | 2.38 |
| ƒ/8 | 1.19 | 1.36 | 1.6 | 1.87 | 2 | 2.26 | 2.44 | 2.65 | 2.82 | 3.16 | 3.39 |
| ƒ/11 | 1.63 | 1.87 | 2.19 | 2.57 | 2.75 | 3.1 | 3.36 | 3.64 | 3.87 | 4.34 | 4.67 |
| ƒ/16 | 2.38 | 2.72 | 3.19 | 3.73 | 4.01 | 4.52 | 4.89 | 5.3 | 5.64 | 6.31 | 6.79 |
| ƒ/22 | 3.27 | 3.73 | 4.39 | 5.13 | 5.51 | 6.21 | 6.72 | 7.28 | 7.75 | 8.68 | 9.34 |
| ƒ/32 | 4.75 | 5.43 | 6.38 | 7.47 | 8.01 | 9.03 | 9.78 | 10.59 | 11.27 | 12.63 | 13.58 |
| 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 Canon EOS RP. The same pixel pitch gives the same diffraction limits.
- Canon EOS 6D Mark II (5.75 μm)
- Sony α7 II (5.92 μm)
- Leica SL2-S (5.93 μm)
- Panasonic Lumix DC-S5 (5.93 μm)
- Panasonic Lumix DC-S5 II (5.93 μm)
- Sony α7 III (5.93 μm)
Pixel pitch comes from the camera database. Send a correction if anything here is wrong.