Sony DSC-R1 read noise vs ISO

The Sony DSC-R1 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 12.91 DN, or 10.5 electrons at the sensor. From ISO 200 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise. Full well at base ISO is about 12,866 electrons; unity gain is around ISO 160.