Cameras with longer battery life can take more photos before exhausting their batteries.
Special note: The measurement standard for battery life stipulates that if a camera has an internal flash, it must be used for 50% of photos taken. For this reason, comparisons of one camera with an internal flash to another without will not be comparable
Cameras with more dynamic range allow you to take photos with dramatic differences in highlight and shadow areas while retaining detail in both.
Think of a brilliant sunset on a rocky beach: Bright sunset in the background, with dark rocks in the foreground. High dynamic range means more of the extremes will be faithfully reproduced.
Dynamic range test data courtesy of DxO Mark.E-M1 test data on DxO Mark 60D test data on DxO Mark
Excellent 18-megapixel sensor with superb detail; Very good high ISO performance, especially for 18-megapixel subframe sensor; 3.0-inch, 1,040K-dot Vari-angle LCD is very useful for video and Live View; Sharp 18-135 kit lens with above average zoom range and I.S.; Full HD (1920x1080) movies at 30/25/24p, 60/50p at 1280x720.
Body not as rugged as mag-alloy 50D; AF assist only works when flash is up, though flash can be forced off; Auto-exposure not reliable in very low light; No continuous autofocus in Movie mode.
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.