Panasonic Lumix DMC-FZ2500 vs Panasonic Lumix DMC-FZ28: read noise comparison

The Panasonic Lumix DMC-FZ2500 was measured at 26 ISO settings from ISO 80 to ISO 25600. Values are Bill Claff's (Photons to Photos) direct measurements from raw files.

At base ISO (80) read noise is 0.54 DN, or 2.8 electrons at the sensor. From ISO 1250 up the camera is effectively ISO-invariant: raising ISO further doesn't meaningfully lower shadow noise. Settings above ISO 12800 don't change analog gain (digital push). Full well at base ISO is about 20,770 electrons; unity gain is around ISO 420.

The Panasonic Lumix DMC-FZ28 was measured at 5 ISO settings from ISO 100 to ISO 1600. Values were derived by Bill Claff from DxOMark lab data.

At base ISO (100) read noise is 3.58 DN. A second gain (dual gain) kicks in at ISO 1600, cutting input-referred read noise by about 1.9 stop. Read noise keeps falling across the measured range, so the camera isn't fully ISO-invariant there.