Patent ID: 8223440
Filing Date: 2012-07-17
Classification: G02B

Abstract:
1. A zoom lens system, comprising in order of from an object side to an image side: a first lens unit having a positive refractive power, which does not move for zooming; a second lens unit having a negative refractive power for a magnification action; and a rear lens group including two or more lens units, wherein the first lens unit includes a first sub lens unit which does not move for focusing and a second sub lens unit which moves for focusing, and the first sub lens unit includes two or more negative lenses and one or more positive lenses; and wherein the following conditional expressions are relative, where νna and θna represent an average Abbe number and an average partial dispersion ratio of materials of the two or more negative lenses included in the first sub lens unit, respectively, νpa and θpa represent an average Abbe number and an average partial dispersion ratio of materials of the one or more positive lenses included in the first lens unit, respectively, fins represents a combined focal length of the two or more negative lenses included in the first sub lens unit, and ft represents a focal length of the zoom lens system at a telephoto end.