TREN
Nikon D1X read noise vs ISO
The Nikon D1X was measured at 11 ISO settings from ISO 125 to ISO 3200. Values are Bill Claff's (Photons to Photos) direct measurements from raw files.
At base ISO (125) read noise is 2.17 DN, or 17 electrons at the sensor. From ISO 160 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise. Settings above ISO 800 don't change analog gain (digital push). Full well at base ISO is about 32,107 electrons; unity gain is around ISO 980.
Nikon D1X read noise table
| ISO | Read noise (DN) | log₂ |
|---|---|---|
| 125 | 2.173 | 1.12 |
| 160 | 2.549 | 1.35 |
| 200 | 3.182 | 1.67 |
| 250 | 3.811 | 1.93 |
| 320 | 4.691 | 2.23 |
| 400 | 5.897 | 2.56 |
| 500 | 7.311 | 2.87 |
| 640 | 9.318 | 3.22 |
| 800 | 11.392 | 3.51 |
| 1600 | ○ 22.785 | 4.51 |
| 3200 | ▲ 45.570 | 5.51 |