Patent ID: 8379317
Filing Date: 2013-02-19
Classification: G02B

Abstract:
1. A zoom lens system having a plurality of lens units, each lens unit being composed of at least one lens element, the zoom lens system, in order from an object side to an image side, comprising: a front unit having negative optical power as a whole, and including a first lens unit located closest to the object side; and a rear unit having positive optical power as a whole, wherein at least the front unit moves along an optical axis in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit is composed of at most three lens elements, the rear unit includes a lens unit having an aperture diaphragm between lens elements, an air space between which is not varied in zooming, a sub lens unit comprising a part of a lens unit constituting the rear unit moves in a direction perpendicular to the optical axis to optically compensate image blur, and the following conditions (1) and (2) are satisfied: here, ω where BF is a back focal length of the entire system at a wide-angle limit, f THs is a center-axis interval between the image-side surface of a lens element located nearest the object side of the aperture diaphragm, and the aperture diaphragm itself, R ω FNO