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.EOS M10 test data on DxO Mark J4 test data on DxO Mark
User-friendly design; great touchscreen interface; good image quality
No viewfinder; limited physical controls; sub-par continuous shooting; lacking video features