FujiFilm GFX 100S vs FujiFilm GFX 100S II: read noise comparison

The FujiFilm GFX 100S was measured at 26 ISO settings from ISO 50 to ISO 102400. Values are Bill Claff's (Photons to Photos) direct measurements from raw files.

At base ISO (100) read noise is 5.13 DN, or 3 electrons at the sensor. A second gain (dual gain) kicks in at ISO 500, cutting input-referred read noise by about 1 stop. From ISO 1250 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise. Settings above ISO 12800 don't change analog gain (digital push). Full well at base ISO is about 38,467 electrons; unity gain is around ISO 60.

The FujiFilm GFX 100S II was measured at 27 ISO settings from ISO 40 to ISO 102400. Values are Bill Claff's (Photons to Photos) direct measurements from raw files.

At base ISO (80) read noise is 3.41 DN, or 3.5 electrons at the sensor. A second gain (dual gain) kicks in at ISO 500, cutting input-referred read noise by about 1.4 stop. From ISO 1000 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise. Settings above ISO 12800 don't change analog gain (digital push). Full well at base ISO is about 41,871 electrons; unity gain is around ISO 60.