TREN
Leica SL3-S read noise vs ISO
The Leica SL3-S was measured at 37 ISO settings from ISO 50 to ISO 204800. Values are Bill Claff's (Photons to Photos) direct measurements from raw files.
At base ISO (100) read noise is 1.64 DN, or 9.8 electrons at the sensor. A second gain (dual gain) kicks in at ISO 640, cutting input-referred read noise by about 1.4 stop. From ISO 51200 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise. Full well at base ISO is about 95,292 electrons; unity gain is around ISO 600.
Leica SL3-S read noise table
| ISO | Read noise (DN) | log₂ |
|---|---|---|
| 50 | ○ 1.366 | 0.45 |
| 64 | ○ 1.474 | 0.56 |
| 80 | ○ 1.591 | 0.67 |
| 100 | 1.636 | 0.71 |
| 125 | 1.778 | 0.83 |
| 160 | 1.972 | 0.98 |
| 200 | 2.189 | 1.13 |
| 250 | 2.497 | 1.32 |
| 320 | 2.949 | 1.56 |
| 400 | 3.482 | 1.80 |
| 500 | 4.084 | 2.03 |
| 640 | 2.000 | 1.00 |
| 800 | 2.250 | 1.17 |
| 1000 | 2.603 | 1.38 |
| 1250 | 3.053 | 1.61 |
| 1600 | 3.580 | 1.84 |
| 2000 | 4.408 | 2.14 |
| 2500 | 5.315 | 2.41 |
| 3200 | 6.453 | 2.69 |
| 4000 | 7.727 | 2.95 |
| 5000 | 9.646 | 3.27 |
| 6400 | ▼ 10.556 | 3.40 |
| 8000 | ▼ 12.641 | 3.66 |
| 10000 | ▼ 15.562 | 3.96 |
| 12800 | ▼ 18.896 | 4.24 |
| 16000 | ▼ 22.627 | 4.50 |
| 20000 | ▼ 27.665 | 4.79 |
| 25600 | ▼ 33.591 | 5.07 |
| 32000 | ▼ 40.786 | 5.35 |
| 40000 | ▼ 49.867 | 5.64 |
| 51200 | ▼ 60.129 | 5.91 |
| 64000 | ▼ 72.004 | 6.17 |
| 80000 | ▼ 88.647 | 6.47 |
| 102400 | ▼ 109.137 | 6.77 |
| 128000 | ▼ 133.436 | 7.06 |
| 160000 | ▼ 165.421 | 7.37 |
| 204800 | ▼ 205.074 | 7.68 |