Canon EF Lens Technology

Image Stabilization

No matter how great the lens is, camera shake can spoil the shot. Blurred photos due to camera shake usually occur when the shutter speed is slower than the reciprocal of the lens focal length. For example, a shutter speed slower than 1/200 sec. at the 200mm focal length can invite a blurred photo caused by camera shake. In such cases, a tripod is necessary. However, a tripod can be a heavy and troublesome burden when you go hiking or traveling. There are even places where using tripods is prohibited. Using a slow shutter speed then becomes difficult.

To resolve this problem, Canon became the first manufacturer to incorporate an Image Stabilizer in an SLR camera lens. Canon's Image Stabilizer (IS) technology makes handheld photography possible in more low-light situations than ever before. When camera shake occurs using normal lenses without image stabilization technology, the image projected to the focal-plane also shakes, often resulting in blurred images at shutter speeds less than 1/focal length. When this same movement occurs with an IS lens attached, a special group of lens elements automatically shifts its position, thereby compensating for the shake and stabilizing the image.

Here's how Canon's original Image Stabilization technology works: A high-speed microcomputer built into the lens analyzes electronic Plane signals emitted by vibration-detecting gyro sensors and controls a mechanism that moves the image stabilizing lens group parallel to the focal-plane, resulting in a sharper image. This compensation effectively adds up to three shutter speed steps to your handheld shooting capability depending on the IS lens you choose. Canon's IS lenses are perfect for low light, or situations where a tripod is not convenient.

Except for the EF 28-135mm f/3.5-5.6 IS USM and EF 75-300mm f/4-5.6 IS USM lenses, IS lenses have two IS modes. One is for normal image stabilization and the other is for panned shots. With a monopod, the Image Stabilizer on all IS lenses operates normally as during hand-held shooting. Also, the EF 300mm f/2.8L IS USM, EF 400mm f/2.8L IS USM, EF 500mm f/4L IS USM, and EF 600mm f/4L IS USM lenses have a mechanism that prevents having the Image Stabilizer turned on while the lens is mounted on a tripod.

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