TREN
Olympus System OM-1 Mark II (HR) read noise vs ISO
The Olympus System OM-1 Mark II (HR) was measured at 12 ISO settings from ISO 80 to ISO 1600. Values are Bill Claff's (Photons to Photos) direct measurements from raw files.
At base ISO (200) read noise is 1.97 DN, or 7.8 electrons at the sensor. From ISO 1000 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise. Full well at base ISO is about 60,830 electrons; unity gain is around ISO 790.
Olympus System OM-1 Mark II (HR) read noise table
| ISO | Read noise (DN) | log₂ |
|---|---|---|
| 80 | ○ 2.346 | 1.23 |
| 100 | ○ 2.028 | 1.02 |
| 200 | 1.972 | 0.98 |
| 250 | 2.282 | 1.19 |
| 320 | 2.585 | 1.37 |
| 400 | 3.010 | 1.59 |
| 500 | 3.434 | 1.78 |
| 640 | 4.084 | 2.03 |
| 800 | 4.823 | 2.27 |
| 1000 | 3.945 | 1.98 |
| 1250 | 4.891 | 2.29 |
| 1600 | 5.856 | 2.55 |