Sony FX2 vs Sony FX3: read noise comparison

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.

The Sony FX3 (ILME-FX3) was measured at 41 ISO settings from ISO 40 to ISO 409600. This model has no measurement of its own; the Sony a7S III, which uses the same sensor, is shown.

At base ISO (80) read noise is 1.01 DN, or 14.4 electrons at the sensor. A second gain (dual gain) kicks in at ISO 1600, cutting input-referred read noise by about 3 stop. From ISO 4000 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise. Settings above ISO 102400 don't change analog gain (digital push). Full well at base ISO is about 227,834 electrons; unity gain is around ISO 1140.