What Does Electronic Image Stabilization Mean?
Electronic image stabilization (EIS) is an image enhancement technique using electronic processing. EIS minimizes blurring and compensates for device shake, often a camera. More technically, this technique is referred to as pan and slant, which is the angular movement corresponding to pitch and yaw.
The EIS technique may be applied to image-stabilized binoculars, still/video cameras, and telescopes.
Techopedia Explains Electronic Image Stabilization
EIS corrects the device shaking, normally resulting in noticeable image jittering within each frame of video or each still image. Camera shaking is particularly tricky with still cameras, especially when using slow shutter speeds and/or telephoto lenses. Telescopic lens-shake issues in astronomy accumulate depending on gradual atmospheric variations, which invariably lead to visibly altered object positions.
EIS cannot prevent blur from subject movement or extreme camera shaking, but it is engineered to minimize blur from normal handheld lens shaking. Certain cameras and lenses are built with more aggressive active modes and/or secondary panning features.