TREN
Canon EOS 7D read noise vs ISO
The Canon EOS 7D was measured at 20 ISO settings from ISO 100 to ISO 12800. Values are Bill Claff's (Photons to Photos) direct measurements from raw files.
At base ISO (100) read noise is 6.45 DN, or 12 electrons at the sensor. From ISO 1250 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 26,690 electrons; unity gain is around ISO 190.
Canon EOS 7D read noise table
| ISO | Read noise (DN) | log₂ |
|---|---|---|
| 100 | 6.453 | 2.69 |
| 125 | 8.168 | 3.03 |
| 160 | 5.657 | 2.50 |
| 200 | 7.111 | 2.83 |
| 250 | 9.126 | 3.19 |
| 320 | 8.000 | 3.00 |
| 400 | 9.987 | 3.32 |
| 500 | 12.295 | 3.62 |
| 640 | 12.553 | 3.65 |
| 800 | 15.562 | 3.96 |
| 1000 | 19.027 | 4.25 |
| 1250 | 21.407 | 4.42 |
| 1600 | 26.723 | 4.74 |
| 2000 | 34.535 | 5.11 |
| 2500 | 39.124 | 5.29 |
| 3200 | 49.180 | 5.62 |
| 4000 | ○ 56.103 | 5.81 |
| 5000 | ○ 66.257 | 6.05 |
| 6400 | ○ 79.341 | 6.31 |
| 12800 | ○ 143.013 | 7.16 |