Patent ID: 8405914

Claim:
A zoom lens for forming an image of an object on an image pickup surface of an image pickup element, the zoom lens comprising, in order from an object side thereof: a first lens group with a positive refractive power; a second lens group with a negative refractive power; a third lens group with a positive refractive power; a fourth lens group with a positive refractive power; and a fifth lens group with a negative refractive power, wherein a power of the zoom lens varies by moving the second lens group, the fourth lens group, and the fifth lens group along an optical axis, the first lens group comprises a reflection optical element for bending an optical path by reflecting a light flux, a positive lens, and a negative lens satisfying the following expressions: n 1n >1.90, ν 1n <25, where n 1n is a refractive index of the negative lens in the first lens group at d line, and ν 1n is an Abbe number of the negative lens in the first lens group, wherein the fifth lens group consists of one negative lens and satisfies the following expression: | f W /f 5 |<0.5, where f W is a focal length of a total system of the zoom lens at a wide-angle end, and f 5 is a focal length of the fifth lens group, wherein the zoom lens adjusts a focal point from an infinity distance to a finite distance by moving the fifth lens group.