Abstract: A zoom lens is disclosed, comprising a front lens group including a compensation lens sub-group arranged to move in a direction having a directional component transverse to the optical axis in order to stabilize the image, and a rear lens group positioned in the rear of the front lens group, the front and rear lens groups being moved along the optical axis when zooming is performed.

Abstract: An optical system comprising, from front to rear, a first lens group of positive power, a second lens group of negative power and a third lens group of positive power, wherein deflection of an image is made by parallel decentering the second lens group.

Abstract: An optical system for deflecting an image by decentering a portion of a photographic lens in a direction perpendicular to an optical axis, wherein the decentering aberrations produced by the decentering are reduced.

Abstract: In the stabilized optical system against vibratory motions, a front lens unit restrained from movement in a direction perpendicular to the optical axis is followed rearwardly by a movable lens unit for decentering away from the optical axis to compensate for the image shift resulting from the vibratory motion, satisfying the following conditions:4F.sub.T <.vertline.F.sub.1 .vertline.0.25F.sub.T <.vertline.F.sub.2 .vertline.<0.8F.sub.Twhere F.sub.1 and F.sub.2 are the focal lengths of the front and movable lens units respectively, and F.sub.T is the focal length of the entire lens system.