Patent ID: 9122038
Filing Date: 2015-09-01
Classification: G02B

Abstract:
1. An imaging lens substantially consisting of a first lens group, a stop, and a second lens group in this order from the object side, the imaging lens performing focusing at each object distance by moving the second lens group along the optical axis; the first lens group includes at least a positive lens disposed on the most-object side, a negative meniscus lens with a convex surface toward the object side, a biconcave negative lens, and a cemented lens substantially constituted by two lenses, which are a positive lens and a negative lens, in this order from the object side; the second lens group includes at least a first positive lens with a convex surface toward the image side, which is disposed on the most-object side, a cemented lens substantially constituted by two lenses, which are a positive lens and a negative lens, and a second positive lens with a convex surface toward the image side, in this order from the object side; and conditional expression below is satisfied: f1a: the focal length of the positive lens disposed on the most-object side in the first lens group, and f: the focal length of the entire system at an object at infinity.