TREN
Canon EOS M read noise vs ISO
The Canon EOS M was measured at 9 ISO settings from ISO 100 to ISO 25600. Values are Bill Claff's (Photons to Photos) direct measurements from raw files.
At base ISO (100) read noise is 8.00 DN, or 13.9 electrons at the sensor. From ISO 3200 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise. Settings above ISO 12800 don't change analog gain (digital push). Full well at base ISO is about 24,998 electrons; unity gain is around ISO 170.
Canon EOS M read noise table
| ISO | Read noise (DN) | log₂ |
|---|---|---|
| 100 | 8.000 | 3.00 |
| 200 | 8.515 | 3.09 |
| 400 | 10.339 | 3.37 |
| 800 | 14.520 | 3.86 |
| 1600 | 24.084 | 4.59 |
| 3200 | 41.355 | 5.37 |
| 6400 | 78.793 | 6.30 |
| 12800 | 157.586 | 7.30 |
| 25600 | ▼ 290.018 | 8.18 |