Patent ID: 9720214
Date: 2017-08-01
CPC Classifications: G02B

Claim:
1. A zoom lens system that performs magnification variation by moving a plurality of lens groups along an optical axis to change a distance between the plurality of lens groups, the zoom lens system comprising, in order from an object side: a first lens group having a positive optical power; a second lens group having a negative optical power; a third lens group having a positive optical power; and a fourth lens group, wherein, during magnification variation from a wide angle end to a telephoto end, a distance between the first lens group and the second lens group is increased, a distance between the second lens group and the third lens group is reduced, and a distance between the third lens group and the fourth lens group is reduced; the third lens group includes, in order from the object side, a front lens group and a rear lens group which are separated from each other by a widest air gap on an optical axis in the third lens group; camera-shake correction is performed by moving whole or part of the front lens group as a camera-shake correction lens group in a direction perpendicular to the optical axis; conditional formula (1) below is satisfied: where f3 represents a focal length of the third lens group; and fis represents a focal length of the camera-shake correction lens group; and conditional formula (4) below is satisfied; where f1 represents a focal length of the first lens group.