Shake & Bake: Image Stabilization
Using image stabilization technology makes it possible for you to make acceptable photographs at three to four times slower—than “normal” whatever that is—shutter speeds than would otherwise be impossible without it.
Camera shake causes lens movement during image exposure, which shifts the angle of incoming light relative to the optical axis and results in blurred images. Canon’s IS lenses correct camera shake by shifting optical components in inverse relation to the lens movement which maintains the position of incoming light rays on the film or capturing element and helps prevent blur. The heart of Canon IS Lenses is their compact and lightweight image stabilizer unit that houses sensors, actuators, and an optical correction system that works with a high-speed microcomputer and two vibration gyros that enable reliable and accurate camera shake correction.
Nikon’s VR technology uses two types of sensors in the lenses to detect pitching (on the vertical axis) and yawing (on the horizontal axis) to identify the direction and scale of shaking at the time of exposure. Commands are sent to two Voice Coil Motors (VCMs) that move the VR lens element group in a particular direction. One motor controls the vertical compensation, the other controls horizontal, with both working together to compensate for diagonal movement. An on-board processor translates motion to the VR element group inside the lens that is moved to counter the detected motion. If you can normally hand hold a camera and lens at 1/125th second, the latest generation of Nikon VRII technology increases this as much as four shutter speeds slower.
Caption: After dinner at the Ponce Yacht & Fishing Club in Puerto Rico I was walking past these boats (above) and wondered what the Olympus E-3 could do—hand held—in the moonlight. Even handholding, the shot is remarkably sharp due to the E-3’s mechanical image stabilization. Exposure was 0.6 sec at f/3.5 and ISO 2000. Lens was the ED 12-60mm at 27mm.
Olympus and Pentax, and Sony offer in-camera stabilization that work in similar ways. The Shake Reduction (SR) system in the Olympus E-3 body used to make the above image uses Supersonic Wave Drive motors that collect information about camera shake from a gyro that detects and analyzes vibrations and moves the imaging sensor using a piezoelectric element. The Pentax system is designed to minimize camera shake by using magnetic force to move the CCD image sensor vertically and horizontally at high speed, while adjusting the speed of oscillation in proportion to the amount of shake detected by a sensor built-into the camera body.