Patent ID: 9097882
Filing Date: 2015-08-04
Classification: G02B

Abstract:
1. A zoom lens system comprising a negative first lens group, a positive second lens group, and a positive third lens group, in that order from the object side, wherein upon zooming from the short focal length extremity to the long focal length extremity, the distance between said first lens group and said second lens group decreases, and the distance between said second lens group and said third lens group increases, wherein said second lens group includes a positive first sub-lens group and a negative second sub-lens group, in that order from the object side, wherein said second sub-lens group comprises a focusing lens group which is moved along the optical axis direction during a focusing operation, and wherein the following condition (1) is satisfied: F2 designates the focal length of said second lens group, and F2B designates the focal length of said second sub-lens group; wherein said second sub-lens group consists of a single lens element; and wherein focusing on an object at infinity to an object at a finite distance is performed by moving said second sub-lens group toward the image side.