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.GR II test data on DxO Mark E-M1 test data on DxO Mark
Exceptional rugged, weather-proof, professional build; Lightning fast contrast-detect AF, and phase-detect AF that makes Four Thirds lenses far more responsive; Tons of useful physical controls with immense customizability; Arguably the best image quality of any Micro Four Thirds camera we've tested to date; Large, sharp, high-resolution electronic viewfinder; Advanced Wi-Fi capabilities, including remote control shooting in PASM exposure modes.
Bigger and heavier than many other compact system cameras; Most expensive Micro Four Thirds camera on the market to date; Menu system and customization options have a steep learning curve; No optical low-pass filter means greater risk of moire; No built-in flash.
Shooting with a wide prime helps you see new shots; Good performance and fast autofocus; Excellent sharp, bright lens; Very customizable; In-camera Wi-Fi works with more than just Android and iOS; Supports Pentax wireless flash strobes
Fixed, wide prime lens isn't for everyone; Cramped controls; Burst capture is slower for JPEGs; Tends too warm under incandescent lighting; Wi-Fi app is poor, and web browser control has cluttered interface