Canon PowerShot G16 vs Canon PowerShot G3 X: read noise comparison

The Canon PowerShot G16 was measured at 23 ISO settings from ISO 80 to ISO 12800. Values are Bill Claff's (Photons to Photos) direct measurements from raw files.

At base ISO (80) read noise is 1.33 DN, or 2.7 electrons at the sensor. From ISO 500 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise. Settings above ISO 3200 don't change analog gain (digital push). Full well at base ISO is about 8,075 electrons; unity gain is around ISO 160.

The Canon PowerShot G3 X was measured at 8 ISO settings from ISO 125 to ISO 12800. Values were derived by Bill Claff from DxOMark lab data.

At base ISO (125) read noise is 4.69 DN. From ISO 1600 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise.