Battling camera shake? Camera and lens manufacturers lend a hand.
It's true: If the camera moves during an exposure, the resulting image won't be sharp; and if you handhold the camera, it will move during exposure. Some people can hold a camera more steadily than others, and faster shutter speeds reduce the effects of camera shake, but some shake—and thus some unsharpness—is always there with a handheld camera. The higher the magnification and the longer the exposure time, the more blurred a handheld image will be.
A tripod is the obvious solution to handheld camera shake. Don't handhold the camera; instead, lock it onto a solid support. But using a tripod isn't always convenient, nor is it always permitted. So camera and lens manufacturers have come up with a number of ways to stabilize handheld cameras and lenses.
There are three basic types of stabilization in still cameras today: lens-shift, sensor-shift and electronic. Each has its advantages.
With lens-shift stabilization, sensors in the lens detect camera shake, then the system shifts a group of internal lens elements to counteract the motion and keep the image in one spot on the image sensor (or film, as stabilizer lenses can be used on 35mm SLRs as well as D-SLRs). Because the image is stabilized before entering the camera, you see a stabilized image in the viewfinder, too. That's the main advantage of lens-shift stabilization. The drawback is that you have to buy special stabilizer lenses, and stabilization might not be available in the focal length you want.