Patent ID: 8964303
Filing Date: 2015-02-24
Classification: G02B

Abstract:
1. A zoom lens comprising: in order from an object side to an image side, (a) a first lens unit having a positive refractive power; (b) a second lens unit having a negative refractive power; (c) a third lens unit having a positive refractive power; and (d) a fourth lens unit having a positive refractive power, wherein, during zooming, the first lens unit is fixed and at least the second lens unit and the fourth lens unit are moved, wherein the third lens unit includes a cemented lens that is formed by cementing a negative lens having a meniscus shape convex towards the object side and a positive lens, wherein the fourth lens unit includes a cemented lens that is formed by cementing a negative lens having a meniscus shape convex towards the object side and a positive lens, and wherein the following conditional expression is met: where f 3 and f 4 are focal lengths of the third lens unit and the fourth lens unit respectively.