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.A7S test data on DxO Mark E-P5 test data on DxO Mark
Handsome retro styling; Very good image quality and dynamic range, with competitive high ISO performance; Lightning fast autofocusing; Excellent burst speeds (nearly 10fps at full res); Top shutter speed of 1/8000 second; Sharp, bright 17mm f/1.8 kit lens; 3-inch tilting touchscreen LCD with 1.04M dots of resolution.
Heavier than some mirrorless models; Weak flash; Below average battery life; No built-in viewfinder (but EVF available in a kit or for separate purchase); A bit pricey compared to the similar E-M5, which offers a built-in EVF and weather sealing at about the same price.
Outstanding high ISO performance; excellent dynamic range; 4K video recording (via uncompressed HDMI); XAVC S option for HD video; Slightly improved battery life over A7/A7R; Built-in Wi-Fi & NFC connectivity.
4K video requires expensive external recorder; Sluggish startup time; Loud shutter; Silent Shooting mode hurts image quality; Lacks a built-in, pop-up flash; Limited selection of native Sony FE lenses.