TREN
Canon EOS Ra read noise vs ISO
The Canon EOS Ra was measured at 27 ISO settings from ISO 100 to ISO 40000. Values are Bill Claff's (Photons to Photos) direct measurements from raw files.
At base ISO (100) read noise is 1.92 DN, or 9.1 electrons at the sensor. From ISO 5000 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise. Full well at base ISO is about 75,089 electrons; unity gain is around ISO 470.
Canon EOS Ra read noise table
| ISO | Read noise (DN) | log₂ |
|---|---|---|
| 100 | 1.919 | 0.94 |
| 125 | 2.713 | 1.44 |
| 160 | 1.866 | 0.90 |
| 200 | 2.099 | 1.07 |
| 250 | 2.908 | 1.54 |
| 320 | 2.114 | 1.08 |
| 400 | 2.694 | 1.43 |
| 500 | 3.555 | 1.83 |
| 640 | 3.227 | 1.69 |
| 800 | 4.084 | 2.03 |
| 1000 | 5.278 | 2.40 |
| 1250 | 5.169 | 2.37 |
| 1600 | 6.453 | 2.69 |
| 2000 | 8.112 | 3.02 |
| 2500 | 8.815 | 3.14 |
| 3200 | 11.314 | 3.50 |
| 4000 | 14.320 | 3.84 |
| 5000 | 15.032 | 3.91 |
| 6400 | 18.636 | 4.22 |
| 8000 | 23.103 | 4.53 |
| 10000 | 29.651 | 4.89 |
| 12800 | 37.271 | 5.22 |
| 16000 | 46.851 | 5.55 |
| 20000 | 57.680 | 5.85 |
| 25600 | 72.004 | 6.17 |
| 32000 | 92.411 | 6.53 |
| 40000 | 114.563 | 6.84 |