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.Z6 test data on DxO Mark A6300 test data on DxO Mark
Excellent image quality; Improved high-ISO performance; Better JPEG quality; Fast autofocus; Very good subject tracking with real-time live view feature; All-magnesium body construction; 4K video.
Slow buffer clearing (no UHS-II support); No touchscreen, Clunky menus; Wi-Fi can be a bit frustrating to use.
Great image quality; Terrific high ISO performance; Fast AF speeds; Eye AF; Swift 12fps burst shooting; In-body image stabilization; High-quality 4K video; Robust build quality; Familiar Nikon design.
Single XQD card slot; Default high ISO NR a bit strong; No 4K 60p; 1/200s x-sync speed; Limited native lens selection (at this time).