The present invention relates to a deflection unit (10) having an optical element (20), which partly reflects a first wavelength and which partly transmits a different, second wavelength. The deflection unit defines an operating beam path traversed by the operating beam (14) from a first window (12) to a second window (24) via a reflection at the optical element (20). The deflection unit comprises an XY-deflection device (22), which is arranged in the operating beam path in order to scan the operating beam that has emerged, a focusing device (16) for focusing the operating beam (14), wherein the focusing device has a variable focal length and is arranged in the operating beam path between the first window (12) and the optical element (20).

A finite conjugate optical assembly, comprising a lens with a core zoom module that includes five optical groups that are configured to exhibit at least 1.58 mm.sup.2sr of etendue at a lowest magnification position, and a ratio of highest to lowest magnification of at least 7:1, and to provide a maximum magnification of 2× or greater.

A finite conjugate lens assembly including an afocal zooming component that has five optical groups that are configured to provide a ratio of highest to lowest magnification between 5.5:1 and 16:1. A lens attachment module and rear adapter module may be disposed, respectively, on an object side and an image side of the optical assembly. The lens assembly may exhibit an approximate etendue between 0.95 and 4.65 mm.sup.2sr, and may be configured in accordance with between 6.6 MP and 32 MP image sensors.

A finite conjugate optical assembly including a core zoom module that includes five optical groups that are configured to provide a ratio of highest to lowest magnification between 5.5:1 and 16:1. A lens attachment module and rear adapter module may be disposed, respectively, on an object side and an image side of the optical assembly. The optical assembly may exhibit an approximate etendue between 0.95 and 4.65 mm.sup.2sr, and may have a magnification of 2× or more at one or more points of the zoom. The optical assembly may be configured in accordance with between 6.6 MP and 32 MP image sensors.

An imaging optical system includes a plurality of lenses, and the plurality of lenses includes a lens pair consisting of two lenses arranged near each other, in which radii of curvature of two surfaces arranged near each other is close to each other, and which satisfies predetermined conditional expressions.

An optical system LO includes in this order from an object side to an image side, a first lens unit FL, an aperture stop SP, and a second lens unit RL having a positive refractive power. The first lens unit FL includes at least three negative lenses including in order from the object side to the image side, negative lenses (G1N), (G2N), and (G3N). At least one lens surface of the negative lenses (G1N), (G2N), and (G3N) is an aspherical surface that satisfies a predetermined conditional inequality.

A lens module includes a plurality of lenses, an annular body and a reflective element. The reflective element, the lenses and the annular are sequentially arranged along an optical axis from an object side to an image side. The lenses include a first lens that is disposed closest to the object side, and a second lens that is disposed closest to the image side. The reflective element is disposed between the object side and the first lens. The annular body is disposed between the object side and the first lens, between the lenses, or between the second lens and the image side. The lens module satisfies 0.5 mm<EPA/PL<5.5 mm where EPA is an area of an entrance pupil of the lens module, and PL is a length of the reflective element.

A high etendue modular finite conjugate lens assembly has a zooming component with multiple lens groups, including four lens groups that each feature a doublet, and a lens attachment lens assembly comprising a fifth doublet, wherein the lens assembly is configured to exhibit between 0.45 and 4.65 mm.sup.2sr of etendue, and a ratio of highest to lowest magnification between 5.5:1 and 16:1, and a magnification of at least 2× at one or more points of a zoom range.

A modular finite conjugate zoom lens assembly with five lens groups each including a doublet, wherein two or three movable lens groups are disposed between a pair of static lens groups.

A zoom lens forms an intermediate image at a position conjugate to a reduction side imaging plane and forms the intermediate image again on a magnification side imaging plane. The zoom lens includes a plurality of lens groups including at least two movable lens groups, which move by changing spacings between the groups adjacent to each other in a direction of an optical axis during zooming, at a position closer to the reduction side than the intermediate image. Among the plurality of lens groups, a final lens group closest to the reduction side has a positive refractive power, and remains stationary with respect to the reduction side imaging plane during zooming. The zoom lens satisfies predetermined conditional expressions (1) and (2) about the focal lengths of the movable lens groups.