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.60D test data on DxO Mark GX-20 test data on DxO Mark
Excellent 18-megapixel sensor with superb detail; Very good high ISO performance, especially for 18-megapixel subframe sensor; 3.0-inch, 1,040K-dot Vari-angle LCD is very useful for video and Live View; Sharp 18-135 kit lens with above average zoom range and I.S.; Full HD (1920x1080) movies at 30/25/24p, 60/50p at 1280x720.
Body not as rugged as mag-alloy 50D; AF assist only works when flash is up, though flash can be forced off; Auto-exposure not reliable in very low light; No continuous autofocus in Movie mode.