TREN
Pentax ist DL2 read noise vs ISO
The Pentax ist DL2 was measured at 5 ISO settings from ISO 200 to ISO 3200. Values are Bill Claff's (Photons to Photos) direct measurements from raw files.
At base ISO (200) read noise is 3.01 DN, or 17.4 electrons at the sensor. From ISO 400 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise. Full well at base ISO is about 22,944 electrons; unity gain is around ISO 1160.
Pentax ist DL2 read noise table
| ISO | Read noise (DN) | log₂ |
|---|---|---|
| 200 | 3.010 | 1.59 |
| 400 | 3.531 | 1.82 |
| 800 | 7.013 | 2.81 |
| 1600 | ▲ 13.929 | 3.80 |
| 3200 | ▲ 28.051 | 4.81 |