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 GX8 test data on DxO Mark
Highest resolution Micro Four Thirds camera yet; Great high ISO performance; Very fast autofocus; Fast burst mode with deep buffers; Impressive Dual I.S. system; Great 4K video.
No built-in flash; Slow buffer clearing; Below average battery life; Limited I.S. for 4K video.
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.