Patent ID: 7742231
Filing Date: 2010-06-22
Classification: G02B

Abstract:
1. A zoom lens, comprising: a front group including a plurality of movable lens groups; and a rear group that is provided on an image side of the front group and that includes a negative lens and a positive lens, wherein an image side lens surface of the positive lens is a flat surface, the positive lens is tiltable about a spherical center of its object side lens surface which is convex on the object side, when a lens system is inclined, the positive lens is tilted by angle α in relation to the optical axis of the lens system based on Equation (0) below: where α: an angle formed between a normal line of the image side lens surface of the positive lens provided within the rear group and the optical axis of the lens system; f: a focal length of the overall lens system; θ: an angle of the optical axis of the lens system after being inclined in relation to the optical axis before being inclined; Bf: a distance between the image side lens surface of the positive lens provided within the rear group and the image plane; and n: a refractive index of the positive lens provided within the rear group.