Patent ID: 8467135
Filing Date: 2013-06-18
Classification: G02B

Abstract:
1. A zoom lens comprising: a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, and a rear group including at least two lens units and having a positive refractive power as a whole in an entire zoom range, in order from an object side to an image side, wherein an interval of each of the lens units is configured to change in a zoom operation, the rear group includes a lens unit R having a positive refractive power at the most image side, the lens unit R consists of a positive lens having a biconvex shape, a cemented lens which is made by cementing a positive lens having a biconvex shape and a negative lens having a biconcave shape, and a positive lens having a convex shape surface at the image side, in order from the object side to the image side, an image side surface of the negative lens having a biconcave shape has an aspherical surface shape where a negative refractive power becomes stronger with increasing distance from an optical axis, and the following conditional expressions are satisfied, where f1 is a focal length of the first lens unit, fR is a focal length of the lens unit R, and fw is a focal length of a whole system at a wide-angle end.