Sony a3000 read noise vs ISO

The Sony a3000 (ILCE-3000) was measured at 9 ISO settings from ISO 100 to ISO 16000. Values are Bill Claff's (Photons to Photos) direct measurements from raw files.

At base ISO (100) read noise is 2.57 DN, or 5 electrons at the sensor. From ISO 400 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise. Settings above ISO 6400 don't change analog gain (digital push). Full well at base ISO is about 30,963 electrons; unity gain is around ISO 190.