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 NX20 test data on DxO Mark
High quality images with lots of detail; Excellent graphical user interface is fun to use; Smart implementation of WiFi makes it relatively easy to share photos wirelessly.
Designed so much like a DSLR you may wonder why you shouldn't get a DSLR instead; Some performance issues, particularly slow buffer clearing and shot-to-shot speed; Initial WiFi set-up can be confusing.
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.