TREN
Pentax K-500 read noise vs ISO
The Pentax K-500 was measured at 10 ISO settings from ISO 100 to ISO 51200. Values were derived by Bill Claff from DxOMark lab data.
At base ISO (100) read noise is 0.62 DN. From ISO 1600 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise.
Pentax K-500 read noise table
| ISO | Read noise (DN) | log₂ |
|---|---|---|
| 100 | 0.624 | -0.68 |
| 200 | 0.707 | -0.50 |
| 400 | 1.240 | 0.31 |
| 800 | 2.071 | 1.05 |
| 1600 | 3.249 | 1.70 |
| 3200 | 10.928 | 3.45 |
| 6400 | 21.857 | 4.45 |
| 12800 | 47.835 | 5.58 |
| 25600 | 83.865 | 6.39 |
| 51200 | 167.730 | 7.39 |