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.PEN-F test data on DxO Mark LX100 test data on DxO Mark
Very good image quality; Great performance in most respects; Bright zoom lens with good macro performance; Photographer-friendly body easily fits in a coat pocket or small bag; Roomy, high-res built-in viewfinder; Decent battery life
Won't fit in a pants pocket; Relatively low resolution by modern standards; Zoom lens has only a modest telephoto; Soft corners at wide or tele positions; Aperture dial is too easily bumped; Bundled flash is fairly weak
Highest resolution Olympus 4/3" camera yet; Excellent image quality for its class; Very good dynamic range; Fast autofocus; Fast burst speeds; Lots of fun creative filter options; Built-in EVF, Wi-Fi.
Expensive; No weather sealing; Mediocre battery life; No 4K video; No mic or headphone jacks.