Pentax K-50 vs Pentax K-500: read noise comparison

The Pentax K-50 was measured at 28 ISO settings from ISO 100 to ISO 51200. Values are Bill Claff's (Photons to Photos) direct measurements from raw files.

At base ISO (100) read noise is 0.59 DN, or 7.2 electrons at the sensor. From ISO 400 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise. Settings above ISO 1250 don't change analog gain (digital push). Full well at base ISO is about 49,740 electrons; unity gain is around ISO 1210.

The Pentax K-500 was measured at 10 ISO settings from ISO 100 to ISO 51200. Values were derived by Bill Claff from DxOMark lab data.

At base ISO (100) read noise is 0.62 DN. From ISO 1600 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise.