Canon PowerShot G12 vs Canon PowerShot G15: read noise comparison

The Canon PowerShot G12 was measured at 17 ISO settings from ISO 80 to ISO 3200. Values are Bill Claff's (Photons to Photos) direct measurements from raw files.

At base ISO (80) read noise is 1.41 DN, or 3.5 electrons at the sensor. From ISO 80 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise. Full well at base ISO is about 9,746 electrons; unity gain is around ISO 190.

The Canon PowerShot G15 was measured at 8 ISO settings from ISO 80 to ISO 6400. Values were derived by Bill Claff from DxOMark lab data.

At base ISO (80) read noise is 1.47 DN. From ISO 3200 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise.