TREN
Leica M Monochrom read noise vs ISO
The Leica M Monochrom was measured at 17 ISO settings from ISO 160 to ISO 10000. Values are Bill Claff's (Photons to Photos) direct measurements from raw files.
At base ISO (320) read noise is 7.52 DN, or 13.3 electrons at the sensor. From ISO 320 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise. Full well at base ISO is about 28,787 electrons; unity gain is around ISO 560.
Leica M Monochrom read noise table
| ISO | Read noise (DN) | log₂ |
|---|---|---|
| 160 | ○ 7.568 | 2.92 |
| 320 | 7.516 | 2.91 |
| 400 | 9.318 | 3.22 |
| 500 | 11.713 | 3.55 |
| 640 | 13.833 | 3.79 |
| 800 | 17.148 | 4.10 |
| 1000 | 21.407 | 4.42 |
| 1250 | 27.284 | 4.77 |
| 1600 | 34.535 | 5.11 |
| 2000 | 42.814 | 5.42 |
| 2500 | 54.569 | 5.77 |
| 3200 | 69.071 | 6.11 |
| 4000 | 86.223 | 6.43 |
| 5000 | 109.896 | 6.78 |
| 6400 | 139.102 | 7.12 |
| 8000 | 173.645 | 7.44 |
| 10000 | 219.793 | 7.78 |