TREN
Pentax K20D read noise vs ISO
The Pentax K20D was measured at 7 ISO settings from ISO 100 to ISO 6400. Values were derived by Bill Claff from DxOMark lab data.
At base ISO (100) read noise is 2.55 DN. From ISO 3200 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise.
Pentax K20D read noise table
| ISO | Read noise (DN) | log₂ |
|---|---|---|
| 100 | 2.549 | 1.35 |
| 200 | 4.993 | 2.32 |
| 400 | 7.516 | 2.91 |
| 800 | 11.314 | 3.50 |
| 1600 | 16.223 | 4.02 |
| 3200 | 19.293 | 4.27 |
| 6400 | 37.271 | 5.22 |