Panasonic Lumix DC-S1R read noise vs ISO

The Panasonic Lumix DC-S1R was measured at 31 ISO settings from ISO 50 to ISO 51200. Values are Bill Claff's (Photons to Photos) direct measurements from raw files.

At base ISO (100) read noise is 2.13 DN, or 5.9 electrons at the sensor. A second gain (dual gain) kicks in at ISO 800, cutting input-referred read noise by about 1.2 stop. From ISO 6400 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise. Settings above ISO 25600 don't change analog gain (digital push). Full well at base ISO is about 43,877 electrons; unity gain is around ISO 280.