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.1DX Mark II test data on DxO Mark D810 test data on DxO Mark
Handles even better than its predecessors; Absolutely spectacular images from the 36-megapixel image sensor; Unusually wide sensitivity range for its resolution; Improved performance and buffer depths; Improved video feature set; Impressive low-light autofocus
Prone to moire and false color with some subjects; No longer available with a low-pass filter; Demands excellent lenses for the best detail; White balance tends warm under tungsten lighting
Excellent image quality, especially from RAWs; Fantastic high ISO performance; Fast autofocus with great tracking performance; 14fps burst rate; Amazing buffer capacity; 4K 60p video; Robust build quality.
Very heavy, bulky and expensive; Dual memory card slots use different formats; 29:59 continuous video recording limit; Touchscreen feels underutilized.