is Optical Shift Image Stabilizer ?
|The history of field lenses is a history of zoom ratio/focal length extension. It came to a point|
where the industry thought it would be impossible to push the envelope any further. The telephoto focal lengths of the lens got so long that even the slightest amount of wind or operator movement would cause image shake and viewing the picture became intolerable, this was before Canon announced the incredible magnification DIGISUPER 86 xs zoom lens. Canon, renowned for its optical image stabilization technologies, developed a new stabilization solution for the broadcast field lens, a built-in Optical Shift Image Stabilizer (Shift-IS) to overcome image shaking at telephoto focal length. Now the Shift-IS is employed in the DIGISUPER 100 xs, DIGISUPER 100AF, DIGISUPER 95,DIGISUPER 86IITELE xs,DIGISUPER 86II xs, DIGISUPER 86AF,DIGISUPER 80, DIGISUPER 76,DIGISUPER 75 xs, HJ40x10B IASD-V and HJ40x14B IASD-V.
How the Optical Shift Image Stabilizer Works
The Optical Shift Image Stabilizer (IS) shifts a lens group in parallel to the
image plane. When the lens moves, the light rays from the subject are bent relative
to the optical axis, resulting in a blurred image because the light rays are deflected.
By shifting the IS lens group on a plane perpendicular to the optical axis to
counter the degree of image shake, the light rays reaching the image plane can
Figure shows what happens when the there is a downward movement with the lens.
The center of the image moves downward on the image plane. When the IS lens group
shifts on the vertical plane, the light rays are refracted so that the image center
returns to the center of the image plane. Since image shake occurs in both horizontal
and vertical directions, the IS lens group can shift horizontally and vertically
on a plane perpendicular to the optical axis to counteract the image shake.
Two shake-detecting sensors, one each for yaw and pitch, are used to detect lens
movement. The shake-detecting sensors detect the angle and speed of movement and
send this information to a high-speed 32-bit microcomputer. The microcomputer
then converts the detection signals into drive signals for the IS lens group.
In accordance with the drive signals, the IS lens group actuator moves the IS
lens group and thus counteracting the image shake and maintaining a stable picture.