Canon EOS D30 read noise vs ISO

The Canon EOS D30 was measured at 5 ISO settings from ISO 100 to ISO 1600. Values are Bill Claff's (Photons to Photos) direct measurements from raw files.

At base ISO (100) read noise is 1.65 DN, or 19 electrons at the sensor. From ISO 200 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise. Settings above ISO 800 don't change analog gain (digital push). Full well at base ISO is about 46,046 electrons; unity gain is around ISO 1160.