Patent ID: 8908298

Claim:
A zoom lens system comprising a positive first lens group, a negative second lens group, and a positive rearward-remaining 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 increases, the distance between said second lens group and said rearward-remaining lens group decreases, and at least said first lens group and at least part of said rearward-remaining lens group moves in the optical axis direction of said zoom lens system, wherein said second lens group includes a negative first sub-lens group which does not move in the optical axis direction during a focusing operation, and a negative second sub-lens group which moves in the optical axis direction during a focusing operation, in that order from the object side; wherein said positive rearward-remaining lens group includes at least two lens groups, the distance therebetween mutually changing during zooming from the short focal length extremity to the long focal length extremity; wherein said second sub-lens group comprises a single lens element; and wherein the distance between said first sub-lens group and said second sub-lens group remains constant during zooming from the short focal length extremity to the long focal length extremity.