Sony FX2 read noise vs ISO

The Sony FX2 (ILME-FX2) was measured at 37 ISO settings from ISO 50 to ISO 204800. This model has no measurement of its own; the Sony a7 IV, which uses the same sensor, is shown.

At base ISO (100) read noise is 1.12 DN, or 4.6 electrons at the sensor. A second gain (dual gain) kicks in at ISO 400, cutting input-referred read noise by about 1.4 stop. From ISO 3200 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise. Settings above ISO 51200 don't change analog gain (digital push). Full well at base ISO is about 65,432 electrons; unity gain is around ISO 410.