Maximum effective ISO is an estimate of the highest sensitivity at which a camera can capture excellent quality photos.
Cameras with higher effective ISO will be better choices for indoor photography, night shooting, and indoor sports photography, especially if you intend to make large prints.
You can learn more at our glossary entry.
Maximum effective ISO test data courtesy of DxO Mark.NX500 test data on DxO Mark GH5 test data on DxO Mark
Very good image quality with high-resolution files; Excellent high ISO performance with RAW files; Very good dynamic range; Fast AF performance; Compact design with good build quality; Better ergonomics than predecessor; 4K video recording.
High ISO noise reduction too strong; AF struggles in low-light; Buffer depth is shallow with RAW files; No option for EVF; No built-in flash (external one included); 4K Video is cropped with narrower FOV.
20MP sensor; Better per-pixel sharpness; Very good, slightly improved dynamic range and high ISOs; Stellar 4K video up to 60p with no crop; 6K Photo; Dual UHS-II SD slots; Good battery life for its class.
Buffer is deep, but slow to clear; Expensive; Menus still confusing; No optical low-pass filter means greater risk of moire; No built-in flash.