Canon EOS 5D Mark IV vs Canon EOS R5: read noise comparison

The Canon EOS 5D Mark IV was measured at 29 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 2.69 DN, or 11.5 electrons at the sensor. From ISO 5000 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise. Settings above ISO 32000 don't change analog gain (digital push). Full well at base ISO is about 67,871 electrons; unity gain is around ISO 430.

The Canon EOS R5 was measured at 30 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 1.33 DN, or 4.1 electrons at the sensor. A second gain (dual gain) kicks in at ISO 400, cutting input-referred read noise by about 2 stop. From ISO 1600 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 49,605 electrons; unity gain is around ISO 310.