Patent ID: 7995283
Filing Date: 2011-08-09
Classification: G02B

Abstract:
1. A zoom lens, comprising, in order from a magnifying side: a first lens unit having a negative refractive power; a second lens unit having a positive refractive power; and a rear lens group, which includes multiple lens units and has a positive refractive power as a whole, wherein at least two lens units are moved for magnification, wherein a whole lens system of the zoom lens comprises the first lens unit, the second lens unit, and the rear lens group, wherein the first lens unit includes a first lens having a negative refractive power, and wherein the following conditions are satisfied: where R1 and R2 indicate a magnifying side curvature radius and a reduction side curvature radius of the first lens, θgF NL indicates a partial dispersion ratio of the first lens with respect to a g-line and an F-line, νd NL indicates an Abbe number of the first lens, f NL indicates a focal length of the first lens, and fw indicates a focal length of the whole lens system at a wide angle end, and