TREN
Sony a7 read noise vs ISO
The Sony a7 (ILCE-7) was measured at 28 ISO settings from ISO 50 to ISO 25600. Values are Bill Claff's (Photons to Photos) direct measurements from raw files.
At base ISO (100) read noise is 1.21 DN, or 4.4 electrons at the sensor. From ISO 320 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise. Settings above ISO 20000 don't change analog gain (digital push). Full well at base ISO is about 58,090 electrons; unity gain is around ISO 370.
Sony a7 read noise table
| ISO | Read noise (DN) | log₂ |
|---|---|---|
| 50 | ○ 1.206 | 0.27 |
| 64 | ○ 1.414 | 0.50 |
| 80 | ○ 1.647 | 0.72 |
| 100 | 1.206 | 0.27 |
| 125 | 1.395 | 0.48 |
| 160 | 1.636 | 0.71 |
| 200 | 1.932 | 0.95 |
| 250 | 2.313 | 1.21 |
| 320 | 2.751 | 1.46 |
| 400 | 3.364 | 1.75 |
| 500 | 4.084 | 2.03 |
| 640 | 5.098 | 2.35 |
| 800 | 6.233 | 2.64 |
| 1000 | 7.781 | 2.96 |
| 1250 | 9.580 | 3.26 |
| 1600 | 12.042 | 3.59 |
| 2000 | 15.242 | 3.93 |
| 2500 | 19.160 | 4.26 |
| 3200 | 24.084 | 4.59 |
| 4000 | 30.910 | 4.95 |
| 5000 | 38.319 | 5.26 |
| 6400 | 48.503 | 5.60 |
| 8000 | 60.129 | 5.91 |
| 10000 | 76.639 | 6.26 |
| 12800 | 97.006 | 6.60 |
| 16000 | 121.938 | 6.93 |
| 20000 | 153.277 | 7.26 |
| 25600 | ▼ 156.498 | 7.29 |