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.
A9 test data on DxO Mark K-5 II test data on DxO MarkCompact yet control-rich body packs in the features; Updated autofocus system focuses in near-darkness; Fully weather-sealed; Sharp, detailed images with very good dynamic range; In-body image stabilization; Dual-axis level with horizon correction.
Can seem intimidating at first; Fewer autofocus points than competitors; Doesn't take advantage of high-speed UHS-I flash cards; Movie feature set is very dated and file sizes huge.
New sensor offers incredible performance; Excellent image quality at low & high ISOs; Very good dynamic range; Phenomenal 20fps burst speed & deep buffer; Very good battery life for a mirrorless; 4K video; Dual card slots.
Slow buffer clearing; Only one card slot is UHS-II compatible; Touchscreen underutilized; No lossless RAW compression option; No 4K/60p option.
