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 T6i test data on DxO Mark
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.
Highest resolution Canon APS-C camera yet; Improved dynamic range over T5i; Good high ISO performance for its class; Very fast autofocus; Built-in Wi-Fi with NFC; Touchscreen tilt/swivel LCD.
Shallow buffer depth with RAW files; Below average battery life; No Servo AF in Live View; No 60p video frame rate.