Abstract:
A zoom lens system comprising a plurality of lens units each being composed of at least one lens element, and comprising, in order from an object side to an image side, a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, a fourth lens unit having positive optical power, and a fifth lens unit having negative optical power, wherein the first lens unit is composed of two or less lens elements, the third lens unit is composed of five or more lens elements, and the condition: 5.0
Abstract:
A zoom lens system includes: a first lens group having positive power; a second lens group having negative power; and following lens groups. The following lens groups include: a first focus lens group having negative power; and a second focus lens group having positive power, arranged adjacent to, and closer to the image than, the first focus lens group. The first and second focus lens groups move along an optical axis during focusing from an infinity focus point on a close focus point. During zooming from a wide-angle end toward a telephoto end, intervals between lens groups change with the first lens group fixed with respect to an image plane. The zoom lens system satisfies the Inequality −0.23
Abstract:
An imaging optical system consists of a first lens group having positive power, an aperture stop, a second lens group having positive power, a third lens group having negative power, a fourth lens group having positive power, and a fifth lens group having negative power. The first lens group, the aperture stop, and the second, third, fourth, and fifth lens groups are arranged in this order such that the first lens group is located closer to an object than the aperture stop or the second, third, fourth, or fifth lens group is. While the imaging optical system is focusing to make a transition from an infinity in-focus state toward a close-object in-focus state, the first, third, and fifth lens groups are located at respectively fixed distances from an image plane in a direction aligned with an optical axis, and the second and fourth lens groups move along the optical axis.
Abstract:
A zoom lens system includes at least six lens groups, each of which has power. An interval between each pair of lens groups that are adjacent to each other among the at least six lens groups changes while the zoom lens system is zooming. Each of three lens groups, which are respectively located closest, second closest, and third closest to an image plane, out of the at least six lens groups consists of one or more bonded lenses.
Abstract:
A single focal length imaging optical system, in order from an object side to an image side, comprising: a front unit composed of a plurality of lens elements; an aperture diaphragm; and a rear unit composed of a plurality of lens elements, wherein the front unit, in order from the object side to the image side, includes a lens element having negative optical power, a lens element having negative optical power, and a lens element having positive optical power, and includes a lens element having positive optical power and placed closest to the image side, and the rear unit includes a focusing lens unit which is composed of at least one lens element and moves along an optical axis in focusing from an infinity in-focus condition to a close-object in-focus condition, and a lens element having negative optical power and placed closest to the image side.