HOW IT WORKS
Steady, Ready, Shoot: Making a Camera Hold Still
By IAN AUSTEN
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.
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.
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.
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."
Mr. Lefebure, who was photographing two cars for Audi, mostly relied on
a stabilized-image lens from Canon and a lightweight monopod.
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
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.
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
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.
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.
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
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.