Zoom lens and imaging apparatus

摘要

A zoom lens includes first, second, third, and fourth lens groups respectively having positive, negative, negative, and positive powers. The first lens group includes a first lens subgroup having a negative power, which is fixed while focusing, a second lens subgroup having a positive power, which moves while focusing, and a third lens subgroup having a positive power, which is fixed while focusing. The second lens subgroup includes a positive lens having a surface having a radius of curvature with a smaller absolute value toward the image side; and a cemented lens constituted by a negative lens toward the object side and a positive lens toward the image side, cemented together at a joint surface having a convex surface toward the object side. The focal distance f12 of the second lens subgroup and the focal length fw of the entire system at the wide angle end satisfy the relationship: 3.0

主权项

1. A zoom lens, substantially consisting of:
a first lens group having a positive refractive power, which is fixed while changing magnification; a second lens group having a negative refractive power, which moves from an object side to an image side while changing magnification from a wide angle end to a telephoto end; a third lens group having a negative refractive power, which corrects movement of an imaging surface while changing magnification; and a fourth lens group having a positive refractive power, which is fixed while changing magnification, provided in this order from the object side; the first lens group substantially consisting of: a first lens subgroup having a negative refractive power, which is fixed during focusing operations; a second lens subgroup having a positive refractive power, which moves during focusing operations; and a third lens subgroup having a positive refractive power, which is fixed during focusing operations, provided in this order from the object side; the second lens subgroup substantially consisting of: a positive lens having a surface having a radius of curvature with a smaller absolute value toward the image side; and a cemented lens constituted by a negative lens toward the object side and a positive lens toward the image side, cemented together at a joint surface having a convex surface toward the object side, provided in this order from the magnification side; the second lens subgroup satisfying the following conditional formula:
3.0