TREN
FujiFilm X-A3 read noise vs ISO
The FujiFilm X-A3 was measured at 16 ISO settings from ISO 200 to ISO 6400. Values are Bill Claff's (Photons to Photos) direct measurements from raw files.
At base ISO (200) read noise is 2.50 DN, or 2.6 electrons at the sensor. From ISO 500 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise. Settings above ISO 3200 don't change analog gain (digital push). Full well at base ISO is about 15,848 electrons; unity gain is around ISO 210.
FujiFilm X-A3 read noise table
| ISO | Read noise (DN) | log₂ |
|---|---|---|
| 200 | 2.497 | 1.32 |
| 250 | 2.990 | 1.58 |
| 320 | 3.630 | 1.86 |
| 400 | 4.469 | 2.16 |
| 500 | 5.389 | 2.43 |
| 640 | 6.774 | 2.76 |
| 800 | 8.000 | 3.00 |
| 1000 | 9.918 | 3.31 |
| 1250 | 12.042 | 3.59 |
| 1600 | 15.455 | 3.95 |
| 2000 | 18.765 | 4.23 |
| 2500 | 23.425 | 4.55 |
| 3200 | 29.041 | 4.86 |
| 4000 | ▲ 37.531 | 5.23 |
| 5000 | ▲ 45.887 | 5.52 |
| 6400 | ▲ 58.485 | 5.87 |