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.
A7S II test data on DxO Mark K-30 test data on DxO MarkPentaprism viewfinder is bright and accurate; Weather-sealed body can handle direct rain; Twin control dials make exposure control a snap; Solid build; Great image quality.
Lower resolution than some rivals; Not as small as recent Pentax entry-level and mid-range models; A couple of ergonomic and UI quirks; Shutter isn't the quietest; 18-55 kit lens isn't weather-sealed.
Comfortable and surprisingly compact camera body; Improved low light performance; Built-in image stabilization; Wide range of usable ISOs; More sophisticated autofocus performance; Excellent video capabilities.
Relatively low resolution; Mediocre continuous shooting performance; No built-in flash; No losslessly compressed RAW option.
