Patent ID: 7554747

Claim:
A zoom lens comprising: in order from an object side of the zoom lens, a first group having a positive refractive power; a second group having a negative refractive power, the second group having a configuration in which a first single lens, a second single lens, and a cemented lens of one double-concave lens and one positive lens are arranged in this order from the object side; an aperture stop; a third group having a positive refractive power; and a fourth group having a positive refractive power, wherein when zooming from a wide-angle end to a telephoto end is performed, the first group and the third group are fixed, and the second group is moved to the image side thereof along an optical axis so as to perform the zooming, while the fourth group is moved along the optical axis so as to compensate a fluctuation of an imaging position caused by the zooming and perform focusing, and the second group satisfies condition: 0.9 <|f 2 a/f 2|<1.80 (3) wherein f 2 a designates a focal length of the single lenses closer to the object side than the cemented lens in the second group; and f 2 designates a focal length of the second group.