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 test data on DxO Mark A6500 test data on DxO Mark
Incredibly small body for a fully-featured, full-frame camera; Very high resolution; Hybrid autofocus is reasonably fast and confident; Significantly better burst-shooting performance than A7R; Excellent image quality even at very high sensitivities; Faster x-sync than A7R; Accepts existing Alpha-mount and E-mount lenses, and can optionally crop to APS-C image circle.
Grass-is-greener syndrome when compared to its higher-res sibling; Moderate performance; Loud shutter (but electronic first-curtain helps); Mediocre battery life when using electronic viewfinder; Weak low-light autofocus considering its price; Limited selection of native Sony FE lenses.
Comfortable, premium body with good controls; Touch-screen for subject selection; Hybrid image stabilization system; Excellent image quality; Better high ISO JPEGs than the A6300; Extremely fast 11.1 fps burst capture; Very deep buffers for raw and JPEG alike; 4K video capture with no pixel binning
Pricey for an APS-C camera; JPEG colors aren't the most accurate; Very slow buffer clearing; Laggy touch-pad AF function; Poorly-placed movie button; No headphone jack; Mediocre battery life