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.D7500 test data on DxO Mark D7000 test data on DxO Mark
Very good image quality; Better than average noise vs. detail handling at high ISOs; Very good dynamic range in JPEGs, excellent in RAW files; Lots of high-end features in a relatively compact body; 6 fps burst mode.
Viewfinder not as accurate as specified; Viewfinder doesn't show ISO unless adjusting; No live histogram in Live View mode; No phase-detect Live View AF mode.
New carbon fiber body is light, compact and very comfortable; Same excellent image quality as the flagship D500; Quick 8.2 frames per second burst shooting with generous buffer; Very fast, accurate autofocus; Tilting touch-screen display; Very good battery life; Records ultra high-def 4K and 60fps Full HD too.
Only a single flash card slot; Doesn't support portrait / battery grip accessories; No rear infrared receiver any more; non-CPU AI lenses will be manual only; 4K video comes with a heavy crop; Movie AF is prone to hunting, Extended ISO sensitivities are a gimmick.