TREN
Sony a33 read noise vs ISO
The Sony a33 (SLT-A33) was measured at 8 ISO settings from ISO 100 to ISO 12800. Values were derived by Bill Claff from DxOMark lab data.
At base ISO (100) read noise is 0.82 DN. From ISO 400 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise.
Sony a33 read noise table
| ISO | Read noise (DN) | log₂ |
|---|---|---|
| 100 | 0.824 | -0.28 |
| 200 | 1.283 | 0.36 |
| 400 | 2.219 | 1.15 |
| 800 | 4.500 | 2.17 |
| 1600 | 8.515 | 3.09 |
| 3200 | 17.509 | 4.13 |
| 6400 | 31.779 | 4.99 |
| 12800 | 138.141 | 7.11 |