Digital Photography For Beginners - What Is Image Stabilization?

Canon calls it Image Stabilization, while Nikon refers to it as Vibration Reduction. Both are accurate descriptions. IS (as I will call it from now on) is built into many modern Digital SLR camera lenses, and even standard in some compact cameras. Basically, it is a system of motion sensors which detects any camera movement, and attempts to provide enough compensation to counteract this, thus keeping the image clear - i.e. preventing blurring from camera shake. Many photographers, once they own an IS lens, won’t buy a subsequent lens without it.

Normally, using a standard lens, a tripod would be preferred if you need to deploy a slow shutter speed in order to obtain sufficient light for a correctly exposed image. However, a tripod is not always feasible, (or even allowed in some places) so using an IS lens will enable you to get much sharper images if you are hand-holding your camera in a low light situation.

IS works well in situations where the subject is still. So, if you are taking a portrait of someone, hand held, the image produced would be sharper using an IS lens versus a standard one. However, in situations where your subject is moving (e.g., a speeding sports car) IS will have no beneficial effect. IS reduces camera motion, not subject motion. That said, IS will improve shots where you are using motion panning to freeze a subject, whilst obtaining a blurred background.

Although IS has obvious advantages when used with slow shutter speeds, it also works well at fast shutter speeds, with long lenses. If you were to take a shot at the full end of a 300mm zoom lens, even with a shutter speed of 1/1000 sec you would still expect to achieve optimum sharpness using an IS over a standard lens. Fast shutter speeds reduce vibration, so IS isn’t always helpful, however with long lenses that can magnify vibration IS is beneficial.

Even if you have an IS lens, there is a situation when you should turn the IS functionality off. This may sound strange, but I’ll explain. When you are shooting on a tripod, although the camera is still, the IS feature in the lens is designed to anticipate camera movement. If it doesn’t find any, it tries to look for some. This searching for movement actually causes tiny vibration, which can introduce camera blur. So, the simple rule to follow is - turn IS ON when shooting hand-held, turn IS OFF, when using a tripod.

In closing, it’s worth noting that an IS lens will cost considerably more than its non-IS equivalent. For example, at the time of writing, the Canon EF 70-200mm f4 L USM Lens retails at around $830. The IS version of this lens is $1,500 - almost double the cost.

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