Patent ID: 7315423

Claim:
A zoom lens having an object side and an image side and comprising, arranged along an optical axis in order from the object side as follows: a first lens group having positive refractive power and including a reflecting member having a reflecting surface for folding the optical axis at least approximately ninety degrees; a second lens group having negative refractive power; a third lens group having positive refractive power and having a stop on its image side; and a fourth lens group having positive refractive power; wherein said second lens group and said fourth lens group move along the optical axis during zooming, and said fourth lens group moves along the optical axis during focusing of the zoom lens; said fourth lens group includes a lens component having negative refractive power that is formed by cementing together at least two lens elements, and a lens component having positive refractive power and a meniscus shape with at least one aspheric surface and with its convex surface on the object side; and the following conditions are satisfied: −0.45 <f 2 /Tf <−0.3 0.8 <f 4 /Tf <1.3 where f2 is the focal length of said second lens group, f4 is the focal length of said fourth lens group, and Tf is the focal length of the zoom lens at the telephoto end; wherein said first lens group comprises, in order from the object side: a lens element having negative refractive power and a meniscus shape with its convex surface on the object side; a right-angle prism that provides said reflecting surface; a lens element having positive refractive power and having a convex surface on the image side; and a biconvex lens element.