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.A7S II test data on DxO Mark G85 test data on DxO Mark
Comfortable and surprisingly compact camera body; Improved low light performance; Built-in image stabilization; Wide range of usable ISOs; More sophisticated autofocus performance; Excellent video capabilities.
Relatively low resolution; Mediocre continuous shooting performance; No built-in flash; No losslessly compressed RAW option.
Very good image quality; Very good high ISO performance and dynamic range; Fast and accurate autofocus; Excellent 4K video recording quality and features.
OLPF-less sensor is prone to moiré; Electronic viewfinder struggles in low light; Continuous autofocus is limited to 6fps shooting; Below average battery life.