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 R test data on DxO Mark M (Typ 240) test data on DxO Mark
Very good overall image quality; Good dynamic range & very good high ISO performance; Excellent Dual Pixel CMOS AF performance; Sharp native lenses; Great performance with adapted optics; Compact design; Fully articulating LCD.
Sensor performance lags behind competition; No In-Body Image Stabilization; Sluggish burst speed with C-AF; Mediocre battery life; No 4Kp60; 1.7x 4K crop; Ergonomics could be better.