Leica TL2 read noise vs ISO

The Leica TL2 was measured at 10 ISO settings from ISO 100 to ISO 51200. Values are Bill Claff's (Photons to Photos) direct measurements from raw files.

At base ISO (100) read noise is 3.16 DN, or 9.2 electrons at the sensor. From ISO 25600 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise. Full well at base ISO is about 47,657 electrons; unity gain is around ISO 290.