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.G9X Mark II test data on DxO Mark S120 test data on DxO Mark
Impressive image quality; Improved JPEGs and good high ISO quality for its class; Compact camera body; Fast maximum aperture; Reliable autofocus; Improved performance.
No tilting display; No viewfinder; Lens is not very wide; Slow buffer clearing; Mediocre battery life.