FujiFilm X-T4 vs FujiFilm X-T5: read noise comparison

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.

The FujiFilm X-T5 was measured at 26 ISO settings from ISO 64 to ISO 51200. Values are Bill Claff's (Photons to Photos) direct measurements from raw files.

At base ISO (125) read noise is 1.69 DN, or 2.6 electrons at the sensor. From ISO 800 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 23,211 electrons; unity gain is around ISO 190.