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.D750 test data on DxO Mark D7000 test data on DxO Mark
Very good image quality; Better than average noise vs. detail handling at high ISOs; Very good dynamic range in JPEGs, excellent in RAW files; Lots of high-end features in a relatively compact body; 6 fps burst mode.
Viewfinder not as accurate as specified; Viewfinder doesn't show ISO unless adjusting; No live histogram in Live View mode; No phase-detect Live View AF mode.
Outstanding image quality with great dynamic range and high ISO performance; Class-leading burst rate; Very good 51-pt AF system; AF system works in very low light; Deep, comfortable handgrip; Articulated LCD monitor; Excellent battery life; Uncompressed 4:2:2 HDMI video output; Built-in Wi-Fi.
Buffer fills quickly with 14-bit RAW; Sluggish Live View AF; Shutter speed tops out at 1/4000s; OVF coverage closer to 97%; Weak low-pass filter is great for detail but higher risk of moire.