Google Pixel 2 read noise vs ISO

The Google Pixel 2 was measured at 18 ISO settings from ISO 50 to ISO 3200. Values are Bill Claff's (Photons to Photos) direct measurements from raw files.

At base ISO (50) read noise is 0.72 DN, or 4.2 electrons at the sensor. From ISO 250 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise. Settings above ISO 400 don't change analog gain (digital push). Full well at base ISO is about 5,638 electrons; unity gain is around ISO 290.