MULTIMEDIA Graphic: Moving Pictures Graphic: Shooting With Image Stabilization

Steady, Ready, Shoot: Making a Camera Hold Still

HEN professional photographers use high-powered telephoto lenses, they typically rely on a tripod to keep the camera still and avoid blurred photos. But for Moose Peterson, a wildlife photographer, a tripod was out of the question last month when he was photographing sea otters from a boat in rough seas off the coast of Alaska.

"You're moving, the camera is moving, the sea otters are moving," Mr. Peterson said.

Instead, he used a Nikon zoom lens that has built-in stabilization features. Sensors within the lens detect movement of the camera and lens, and motors alter the positions of the lens elements to compensate. The process is controlled by a microchip, and the result is a sharp photo no matter how much the lens jiggles.

"I have no doubt that I wouldn't have had these sea otter pictures without it," he said.

Camera makers have used electronics to conquer the exposure and focus errors that have traditionally plagued photographers. Now several of them have turned their attention to camera shake.

"Clearly since the beginning of photography there has been a need to help photographers shoot in lower-light conditions and with longer focal length lenses without blurring," said Richard LoPinto, the senior vice president for product technology and engineering at Nikon's United States operation.

Experienced professional photographers with steady hands can produce clear photos at relatively slow shutter speeds, and even amateurs are sometimes lucky. But all photographers eventually reach a limit. And they can't always resort to a tripod, even on land.

At last weekend's 24-hour automobile race in Le Mans, France, for example, Regis Lefebure, a motorsports photographer from Silver Spring, Md., used very high-magnification telephoto lenses. To keep such large lenses steady, Mr. Lefebure said, "you would have to use a very large, very heavy tripod designed for a studio. For motorsports it's impossible."

Instead Mr. Lefebure, who was photographing two cars for Audi, mostly relied on a stabilized-image lens from Canon and a lightweight monopod.

There are several approaches to stabilizing cameras. For aerial shots, feature film crews, television stations and police departments rely on big, gyroscopically stabilized units that steady both camera and lens. But devices that large are impractical for hand-held, still photo cameras.

Many consumer video cameras use an all-electronic system that detects movement and then automatically crops each frame captured by the camera to create a seemingly stable sequence. That approach reduces the overall quality of the images, however, and if used in a high-resolution digital still camera requires a lot of processing power.

In 1987 Canon displayed a prototype image-stabilization lens at a trade show. But Chuck Westfall, who heads the camera technical information department at Canon U.S.A., said that the electronics needed to operate it "were in a large tower-style computer that was hidden under the display table."

By the early 1990's Canon began offering a more practical stabilization system in some consumer video cameras and, a bit later, in binoculars.

The motion sensor developed for those products is still in use. It has a tiny ceramic rod that moves in a track when the lens moves. The rod's movements affect how much light from a light-emitting diode reaches a row of photo sensors.

For the job of keeping the image stable, Canon used two pieces of flat glass that were separated by a bellows containing a transparent silicone-based liquid. Based on the data from the motion sensor, motors moved the two glass plates relative to each other. That change in position compensated for camera shake by shifting the image.

But the extra glass and clear liquid introduced optical distortions that would be apparent in still photos. As a result, Canon designed some new lenses so that a small group of their glass elements could be surrounded by electromagnets. The magnets shift the groups of elements around to counteract camera shake.

Nikon adopted a similar approach in its image-stabilized lenses. But a third Japanese camera maker, Konica Minolta, decided that moving the image-sensing chip made more sense. Right now that feature is available only in a fixed-lens high-end digital camera. But this fall the company will introduce a digital camera with the feature that accepts all of Minolta's interchangeable lenses.

Jon Sienkiewicz, vice president for marketing at the American subsidiary Konica Minolta Photo Imaging, said that Konica's approach gave users the advantage of image stabilization without buying new and generally costly lenses. Minolta also uses piezoelectric actuators rather than conventional motors to move the chip around. The company claims that such devices are able to maintain closer tolerances than motors.

But Mr. Westfall of Canon said that his company would not follow suit. "There are issues with focus accuracy if you've got a system where part of the camera body is moving," he said.