Patent ID: 9170408
Filing Date: 2015-10-27
Classification: G02B,G03B,H04N

Abstract:
1. A zoom lens substantially consisting of, in order from an object side: a first lens group having a positive refractive power; a second lens group having a negative refractive power; a third lens group having a positive refractive power; and a fourth lens group having a positive refractive power, wherein, during magnification change from a wide-angle end to a telephoto end, the first lens group and the third lens group are fixed in an optical axis direction relative to an image plane, the second lens group is moved toward an image side along the optical axis relative to the image plane, and the fourth lens group is moved in the optical axis direction relative to the image plane, the first lens group consists of, in order from the object side, a cemented lens formed by a negative lens and a positive lens cemented together, and two positive lenses, the third lens group consists of, in order from the object side, a front group that is fixed, and a rear group that has a positive refractive power and is able to be shifted in directions intersecting with the optical axis to thereby shift an image formed on the image side, and the condition expressions (1) and (2) below are satisfied: where Rs 1 is a radius of curvature of a most object-side surface of the cemented lens forming the first lens group, Rs 2 is a radius of curvature of a most image-side surface of the cemented lens forming the first lens group, fw is a focal length of the zoom lens at the wide-angle end, and Mz is an amount of movement of the second lens group during magnification change from the wide-angle end to the telephoto end.