Patent ID: 8477429
Filing Date: 2013-07-02
Classification: G02B

Abstract:
1. A zoom lens system comprising, in order from an object side to an image side: a first lens unit which does not move for zooming and has a positive refractive power; a second lens unit which moves to the image side during zooming from a wide angle end to a telephoto end and has a negative refractive power; a third lens unit which moves on an optical axis during zooming; and a fourth lens unit which does not move during zooming and has a positive refractive power, wherein the fourth lens unit is constituted by a front lens subunit having a positive refractive power and a rear lens subunit having a positive refractive power with an air interval therebetween, which air interval being the largest within the fourth lens unit, wherein the front lens subunit and the rear lens subunit each have at least one positive lens and at least one negative lens, wherein the fourth lens unit satisfies the following conditions: wherein the rear lens subunit includes a lens GNL formed of a material having a characteristic satisfying: wherein the Abbe number νd and the partial dispersion ratio θgF with respect to the g-line and the F-line satisfying: