Patent ID: 9651761
Date: 2017-05-16
CPC Classifications: G02B

Claim:
1. A zoom lens comprising, consecutively 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 negative refractive power, a fourth lens group having a positive refractive power, and a fifth lens group having a positive refractive power, wherein the first lens group, the second lens group, the third lens group, the fourth lens group, and the fifth lens group are moved to change distances therebetween during magnification change, a distance between the first lens group and the second lens group at a telephoto end is larger than that at a wide-angle end, a distance between the second lens group and the third lens group at the telephoto end is larger than that at the wide-angle end, a distance between the third lens group and the fourth lens group at the telephoto end is smaller than that at the wide-angle end, and a distance between the fourth lens group and the fifth lens group at the telephoto end is smaller than that at the wide-angle end, positions of the first lens group, the second lens group, the fourth lens group, and the fifth lens group at the telephoto end are closer to the object side than their positions at the wide-angle end, the first lens group consists essentially of, in order from the object side, a negative meniscus lens with the concave surface toward an image side, a positive lens, and a positive lens, the second lens group consists essentially of, in order from the object side, a negative lens with an image side surface having an absolute value of radius of curvature smaller than that of an object side surface thereof, a biconcave lens, and a biconvex lens, the third lens group consists essentially of a negative lens with an object side surface having an absolute value of radius of curvature smaller than that of an image side surface thereof, and the third lens group is moved during focusing, the fifth lens group consists essentially of, in order from the object side, a fifth A lens group having a positive refractive power and consisting essentially of a biconvex lens, and a fifth B lens group having a negative refractive power and consisting essentially of, in order from the object side, a biconcave lens and a biconvex lens, and the condition expression (1) below is satisfied: where f5 is a focal length of the fifth lens group, and f5B is a focal length of the fifth B lens group.