TREN
Phase One IQ4 150MP read noise vs ISO
The Phase One IQ4 150MP was measured at 28 ISO settings from ISO 50 to ISO 25600. Values are Bill Claff's (Photons to Photos) direct measurements from raw files.
At base ISO (100) read noise is 4.17 DN, or 3.5 electrons at the sensor. From ISO 20000 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise. Full well at base ISO is about 54,029 electrons; unity gain is around ISO 80.
Phase One IQ4 150MP read noise table
| ISO | Read noise (DN) | log₂ |
|---|---|---|
| 50 | ○ 4.199 | 2.07 |
| 64 | ○ 4.141 | 2.05 |
| 80 | ○ 4.056 | 2.02 |
| 100 | 4.170 | 2.06 |
| 125 | 4.112 | 2.04 |
| 160 | 4.199 | 2.07 |
| 200 | 7.568 | 2.92 |
| 250 | 7.674 | 2.94 |
| 320 | 7.727 | 2.95 |
| 400 | 6.821 | 2.77 |
| 500 | 6.727 | 2.75 |
| 640 | 7.062 | 2.82 |
| 800 | 12.906 | 3.69 |
| 1000 | 13.642 | 3.77 |
| 1250 | 13.361 | 3.74 |
| 1600 | 25.813 | 4.69 |
| 2000 | 26.173 | 4.71 |
| 2500 | 25.634 | 4.68 |
| 3200 | 50.213 | 5.65 |
| 4000 | 49.867 | 5.64 |
| 5000 | 49.522 | 5.63 |
| 6400 | 95.670 | 6.58 |
| 8000 | 103.250 | 6.69 |
| 10000 | 97.006 | 6.60 |
| 12800 | 181.019 | 7.50 |
| 16000 | 177.294 | 7.47 |
| 20000 | 184.823 | 7.53 |
| 25600 | 372.217 | 8.54 |