Patent ID: 7092170
Filing Date: 2006-08-15
Classification: G02B

Abstract:
1. A three-group zoom lens, comprising, in order from an object side thereof: a first lens group having a negative refractive power, comprising in order from the object side: a second lens group having a positive refractive power, comprising in order from the object side thereof, wherein the first lens group moves to the object side after moving to an image side, the second lens group moves only to the object side, and the third lens group moves in an amount different from that of the second lens group upon focusing an object point at infinity from a wide-angle end to a telephoto end, and the third lens group is configured to be movable for focusing, wherein and the following conditional formula are satisfied: where L t is a distance between a lens surface that is closest to the object side of the three-group zoom lens and the image plane at the telephoto end, f 2 is a focal length of the second lens group, and f 1 is a focal length of the first lens group.