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 III test data on DxO Mark D5300 test data on DxO Mark
Excellent image quality similar to more expensive DSLRs (like the D7100); Great dynamic range; Responsive all-around performer; Excellent Full HD video-shooting quality; Built-in Wi-Fi with remote control and sharing features; Built-in GPS; Compact and lightweight size; 18-140mm kit lens performs well for its type and has a very versatile focus length range.
AA-filterless sensor makes it more prone to moire; Burst speed slows with highest quality 14-bit RAW images; Live View mode not as good as some competitors; No external headphone jack; GPS receiver not very sensitive.
New 24MP sensor offers excellent image quality; Outstanding high ISO performance and dynamic range; Improved JPEG colors; Improved build quality; Fast autofocus; Excellent 4K video; Very good battery life.
Buffer clearing can be slow even with fast UHS-II cards; UHS-II support only on one card slot; No losslessly compressed RAW option; Dedicated battery charger not included; Menus are still confusing; No built-in flash.