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.
EOS M5 test data on DxO Mark NX300 test data on DxO MarkStylish "retro modern" design in two color schemes; attractive 3.3-inch AMOLED tilting touchscreen; new APS-C CMOS sensor with on-chip phase detection AF; better image quality, particularly in low light at high ISOs; faster all-around performance; improved Wi-Fi connectivity.
Camera feels more plasticky than expected when you pick it up; slower shot-to-speeds compared to rivals; poor buffer depth with raw files; aggressive anti-noise processing destroys detail in high ISO shots; display smudges easily and is rather dim; no EVF support.
Enthusiast-oriented compact camera body; Good image quality in most situations; Built-in electronic viewfinder; Impressive Dual Pixel CMOS AF; Very good overall performance.
High ISO image quality and dynamic range aren't quite up to par with some of its competition; No 4K video recording; Native EF-M lens selection is still limited; Below average battery life.
