TREN
Sony a550 read noise vs ISO
The Sony a550 (DSLR-A550) was measured at 7 ISO settings from ISO 200 to ISO 12800. Values were derived by Bill Claff from DxOMark lab data.
At base ISO (200) read noise is 1.40 DN. From ISO 800 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise.
Sony a550 read noise table
| ISO | Read noise (DN) | log₂ |
|---|---|---|
| 200 | 1.404 | 0.49 |
| 400 | 1.879 | 0.91 |
| 800 | 3.681 | 1.88 |
| 1600 | 6.774 | 2.76 |
| 3200 | 13.177 | 3.72 |
| 6400 | 25.457 | 4.67 |
| 12800 | 50.213 | 5.65 |