Patent attributes
A zoom lens that is designed to enable a thinner image pickup device includes, in order from the object side, a first lens group having positive refractive power and a reflecting surface for folding the optical axis of the zoom lens approximately ninety degrees, a second lens group having negative refractive power, a third lens group having positive refractive power with a stop at its image side, and a fourth lens group having positive refractive power. The second lens group and the fourth lens group move along the optical axis during zooming, and the fourth lens group moves along the optical axis during focusing. The four lens groups have particular constructions and the zoom lens satisfies specified conditions related to the focal lengths of specified lens groups, the focal length of the zoom lens at the telephoto end, and the Abbe number of a specified lens element.
