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.E-M1 II test data on DxO Mark K-30 test data on DxO Mark
Pentaprism 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.
Excellent image quality; Very good dynamic range & high ISO performance; Fantastic C-AF performance; Incredible burst rates, even with RAW; 4K UHD & Cinema 4K (DCI) video; Clean HDMI; Dual SD card slots.
Expensive; Menus still confusing; UHS-II support only on one card slot; No optical low-pass filter means greater risk of moire; No built-in flash.