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.A7 test data on DxO Mark E-M1 test data on DxO Mark
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.A7 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.
Incredibly small body for a fully-featured, full-frame camera; Very high resolution; Hybrid autofocus is reasonably fast and confident; Significantly better burst-shooting performance than A7R; Excellent image quality even at very high sensitivities; Faster x-sync than A7R; Accepts existing Alpha-mount and E-mount lenses, and can optionally crop to APS-C image circle.
Grass-is-greener syndrome when compared to its higher-res sibling; Moderate performance; Loud shutter (but electronic first-curtain helps); Mediocre battery life when using electronic viewfinder; Weak low-light autofocus considering its price; Limited selection of native Sony FE lenses.