Patent ID: 8873157

Claim:
A zoom lens system comprising, in order from an enlargement side, a first lens group that remains stationary during zooming and that has a negative optical power and a plurality of lens groups that move during zooming, wherein the first lens group includes three lens groups each having a negative optical power, of the three lens groups, a most enlargement-side lens group is a 1 a -th lens group, a lens group located to a reduction side of the 1 a -th lens group is a 1 b -th lens group, and a lens group located to a reduction side of the 1 b -th lens group is a 1 c -th lens group, the 1 a -th lens group remains stationary during focusing and includes at least one positive lens element, the 1 b -th lens group moves toward a reduction side during focusing from infinity to a close distance, and the 1 c -th lens group moves toward the enlargement side during focusing from infinity to a close distance.