Patent ID: 8804250
Filing Date: 2014-08-12
Classification: G02B

Abstract:
1. A zoom lens comprising, in order from an object: a first lens group having negative refractive power; a second lens group having positive refractive power; and a third lens group having positive refractive power, upon zooming from a wide-angle end state to a telephoto end state, at least the first lens group and the second lens group moving along an optical axis so that a distance between the first lens group and the second lens group decreases, and a distance between the second lens group and the third lens group increases, the lens closest to the object in the second lens group being a positive single lens, the object side lens surface of the positive single lens being an aspherical surface of which radius of curvature increases in a direction from the optical axis to the periphery of the lens, and the following conditional expression being satisfied: where X denotes a sag within an effective diameter on the object side lens surface of the positive single lens, Ymax denotes a maximum image height of the zoom lens in the wide-angle end state, fw denotes a focal length of the zoom lens in the wide-angle end state, and TLw denotes a total length of the zoom lens in the wide-angle end state.