FujiFilm X-T3 (EFCS) vs FujiFilm X-T4: read noise comparison

The FujiFilm X-T3 (EFCS) was measured at 25 ISO settings from ISO 80 to ISO 51200. Values are Bill Claff's (Photons to Photos) direct measurements from raw files.

At base ISO (160) read noise is 1.82 DN. A second gain (dual gain) kicks in at ISO 800, cutting input-referred read noise by about 1.1 stop. From ISO 5000 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).

The FujiFilm X-T4 was measured at 20 ISO settings from ISO 160 to ISO 12800. Values are Bill Claff's (Photons to Photos) direct measurements from raw files.

At base ISO (160) read noise is 1.85 DN, or 5.5 electrons at the sensor. A second gain (dual gain) kicks in at ISO 500, cutting input-referred read noise by about 1.1 stop. From ISO 1600 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise. Full well at base ISO is about 46,164 electrons; unity gain is around ISO 480.