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.5D Mark III test data on DxO Mark 80D test data on DxO Mark
Cameras with more dynamic range allow you to take photos with dramatic differences in highlight and shadow areas while retaining detail in both.
Think of a brilliant sunset on a rocky beach: Bright sunset in the background, with dark rocks in the foreground. High dynamic range means more of the extremes will be faithfully reproduced.
Dynamic range test data courtesy of DxO Mark.80D test data on DxO Mark 5D Mark III test data on DxO Mark
Superb still and video image quality; Powerful, fast, and accurate AF system with loads of cross-type points, loads of configurability and great frame coverage; Rugged, weather-sealed body with great control layout and user-interface configurability.
Dynamic range is limited by noise in deep shadows; Somewhat heavy-handed noise suppression and sharpening at default settings. (Shooting RAW avoids both.); No AF illuminator.
Very good image quality; Better RAW high ISO performance than predecessor; Improved buffer depth; Very fast AF; Dual Pixel CMOS AF is excellent; f/8 AF support; 1080/60p video; Headphone jack; Very good battery life.
New kit lens isn't very sharp; No 4K video; No clean HDMI out; 29:59 minute video recording limit; Phase detect AF not as sensitive in low-light as expected (Dual Pixel AF is better in low-light).