A zoom lens L0 includes a first lens group L1 and a rear group LR disposed in order from an object side to an image side, the first lens group L1 having a negative refractive power and the rear group LR having a positive refractive power as a whole. The rear group LR includes a partial group LP, a partial group LN, and two or more lens groups between which distances change in zooming. When image blur is corrected, the partial group LN moves in a direction including a component of a direction perpendicular to an optical axis. A lens surface closest to the object side among lens surfaces of the partial group LN and a lens surface closest to the image side among the lens surfaces of the partial group LN are both concave surfaces.

A zoom lens includes in order from an object side, a negative first lens unit and a rear lens unit including one or more lens units, an interval between adjacent lens units being changed during zooming, in which the first lens unit and the one or more lens units can be set to first, second and third zoom states, in which angles of view at first and second image heights at the first zoom state are respectively 160° or larger, in which a distortion at the first image height at the third zoom state is −30% or more, and the first image height, the second image height, a total length of the zoom lens at a wide angle end, and a focal length at the wide angle end are appropriately set.

A variable magnification optical system comprising, in order from an object side, a first lens group having negative refractive power, a first intermediate lens group having positive refractive power, a second intermediate lens group having negative refractive power and a rear lens group; upon varying a magnification from a wide angle end state to a telephoto end state, a distance between the first lens group and the first intermediate lens group being varied, a distance between the first intermediate lens group and the second intermediate lens group being varied, and a distance between the second intermediate lens group and the rear lens group being varied; the rear lens group comprising at least one focusing lens group which is moved upon carrying out focusing from an infinitely distant object to a closely distant object; and predetermined conditional expressions being satisfied, thereby the focusing lens group(s) being reduced in weight.

An image forming optical system consists of a first optical system and a second optical system in order from a magnification side. An intermediate image is formed between the first optical system and the second optical system. Among the aspherical lenses included in the first optical system, a specific lens, which is the aspherical lens closest to the intermediate image on the optical path, has a meniscus shape of which a surface is convex toward the reduction side in a paraxial region. The image forming optical system satisfies a maximum image height, a focal length, and predetermined conditional expressions for the specific lens.

A magnification-variable optical system having a small size, a wide angle of view, and high optical performance, an optical apparatus including the magnification-variable optical system, and a method for manufacturing the magnification-variable optical system are provided.

A magnification-variable optical system ZL used for an optical apparatus such as a camera 1 includes a first lens group G1 having a negative refractive power, and a rear group GR including at least one lens group disposed on an image side of the first lens group G1, and is configured so that a distance between lens groups adjacent to each other changes at magnification change and a condition expressed by predetermined condition expressions is satisfied.

A six-piece optical image capturing system is disclosed. In order from an object side to an image side, the optical lenses along the optical axis include a first lens with refractive power; a second lens with refractive power; a third lens with refractive power; a fourth lens with refractive power; a fifth lens with refractive power, and a sixth lens with negative refractive power. At least one lens among the first lens to the fifth lens has positive refractive power. The image-side surface and object-side surface of the sixth lens are aspheric, and at least one of the image-side surface and the object-side surface of the sixth lens has an inflection point. The optical lens of the optical image capturing system can increase aperture value and improve the imagining quality for use in compact cameras.

A variable magnification optical system comprising a plurality of lens groups and, upon varying a magnification, distances between respective lens groups in the plurality of lens groups being varied. The plurality of lens groups comprises an object side focusing lens group which is moved upon carrying out focusing and at least one image side focusing lens group disposed in a more image side than the object side focusing lens group and moved with a trajectory differing from that of the object side focusing lens group, upon carrying out focusing. The predetermined conditional expressions are satisfied. Thus, variations in aberrations upon varying magnification from the wide angle end state to the telephoto end state as well as variations in aberrations upon carrying out focusing from an infinite distance object to a close distance object can be suppressed superbly.

A zoom lens includes a first lens unit having negative refractive power, a second lens unit having positive refractive power, and a rear lens group including one or more lens units. The zoom lens includes an aperture stop. The rear lens group includes a focus lens unit having negative refractive power that is moved to an image side in focusing from an infinite to a close distance and at least one lens unit arranged on the image side of the focus lens unit. The first lens unit includes three or more negative lenses. The focus lens unit includes a cemented lens or a single lens. The zoom lens satisfies a predetermined inequality.

A zoom lens consists of, in order from an object side, a focusing group, a zoom group, and a subsequent group. The focusing group consists of, in order from the object side, a front focusing group which does not move with respect to the image plane during zooming and focusing, a middle focusing group which consists of one or two positive lens groups each moving during focusing, and a rear focusing group which consists of a negative lens group moving during zooming and focusing. The rear focusing group has a zoom range in which the amount of movement during focusing changes in accordance with the zoom position and the rear focusing group moves to the image side during focusing from the object at infinity to the closest object. Predetermined conditional expressions relating to the amount of movement of the rear focusing group are satisfied.

A high magnification MWIR continuous zoom optical system is described herein that consists of the following components: a front detachable extender group, a fixed group for focusing incoming radiation, three moving groups for zooming and generating an intermediate image and a relay group. The mentioned optical system has the ability to work with MWIR radiation (3-5 μm) and generate a thermal image from the gathered radiation. The system also has the ability to zoom continuously in a wide variable focal length range with a high magnification ratio of 20×. With the use of a cooled detector, the combined system allows its user to be able to receive high quality thermal images in all FOV configurations.