Higher-end binoculars and zoom or telephoto lenses for SLR cameras often come with image stabilization. It is also available in digital video cameras with large zooms. Digital cameras with large zoom lenses also come with image stabilization or variants such as anti-shake.
Image stabilization helps to steady the image projected back into the camera by the use of a "floating" optical element —often connected to a fast spinning gyroscope— which helps to compensate for high frequency vibration (hand shake for example) at these long focal lengths. Canon EF SLR lenses with image stabilization have a IS suffix after their name, Nikon uses the VR "Vibration Reduction" suffix on their image stabilised Nikkor lenses.
Typically, image stabilization can help you take handheld shots almost two stops slower than with image stabilization off. For example if you would require a shutterspeed of 1/500s to shoot a particular scene, you should be able to shoot at only 1/125s (4 times slower) with image stabilization. This is very useful when shooting moving subjects in low light conditions by panning and/or when using long focal lengths.
Important footnote: The above "optical" image stabilization is different from the "digital" image stabilization found in some digital video cameras. "Digital" image stabilization only makes sense for digital video as it pixel shifts the image frames to create a more stable video image.
This article is written by Vincent Bockaert,
author of The 123 of digital imaging Interactive Learning Suite
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