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.1DX Mark II test data on DxO Mark D7200 test data on DxO Mark
Rugged, weather-sealed body; Great ergonomics and loads of controls; Accurate optical viewfinder; Excellent image quality; Decent burst speed; Swift autofocus; Generous buffer depths; Superb battery life
Mixes plastic and magnesium-alloy panels on exterior; LCD monitor can't be tilted or swiveled; Presents a steep learning curve; No focus peaking in live view; Video mode feels a bit of an afterthought; New Wi-Fi features are rough around the edges
Excellent image quality, especially from RAWs; Fantastic high ISO performance; Fast autofocus with great tracking performance; 14fps burst rate; Amazing buffer capacity; 4K 60p video; Robust build quality.
Very heavy, bulky and expensive; Dual memory card slots use different formats; 29:59 continuous video recording limit; Touchscreen feels underutilized.