A zoom lens includes, from an object side a first lens unit (a positive refractive power) configured not to move for zooming, two or more intermediate lens units configured to move in zooming, and a rear lens unit (a positive refractive power), wherein an interval between each pair of adjacent lens units changes in zooming, the first lens unit includes, from the object side, a first lens subunit (a negative refractive power) configured not to move for focusing, a second lens subunit (a positive refractive power) configured to move for focusing, and a third lens subunit (a positive refractive power), the zoom lens satisfies specific inequalities concerning a focal length of the first lens unit, a length on an optical axis from a last surface to a rear principal point of the first lens unit, and a focal length of the zoom lens at a telephoto end.

A rear adapter module for a finite conjugate optical assembly and camera is configured to couple with a core zoom module. A lens assembly of the rear adapter module includes three or more lens elements and has a positive focal length. The lens assembly exhibits a pupil size of between 16 and 25 mm and a pupil depth greater than 50 mm.

A zoom lens includes, in order from the object side, a first lens unit having a positive refractive power that does not move for zooming, second to fourth lens units each having a negative refractive power that moves for zooming, and a relay lens unit having a positive refractive power and being closest to the image side that does not move for zooming. The second lens unit moves to the image side from the wide-angle end to the telephoto end. When a focal length fx determined by a focal length fw of the zoom lens at the wide-angle end and a zoom ratio Z is fx=fwZ.sup.0.38, the zoom lens satisfies 0.05<L2 min/L2w<0.98, where L2 min is a minimum distance between the second and third lens units in a zoom range from the wide-angle end to the focal length fx, and L2w is a distance between them at the wide-angle end.

A zoom lens includes, in order from the object side, a first positive lens unit that remains unmoved for zooming, a second negative lens unit that is moved for zooming, one or two zooming lens units that is moved for zooming, and a positive rear lens unit that remains unmoved for zooming. The intervals between adjacent lens units are changed during zooming. The rear lens unit composed of a front sub lens unit within a range satisfying 0<d4a/d4<0.3, where d4 is the thickness of the rear lens unit, and d4a is the distance from the vertex of a lens closest to the object side in the rear lens unit, and a rear sub lens unit outside the range. The average Abbe numbers of convex and concave lenses in the front sub lens unit and the average partial dispersion ratio of the convex lenses are appropriately set.

A zoom lens includes, in order from object-side, a fixed positive first group including three-or-more lenses, a negative second group including a unit moving toward image-side during zooming toward telephoto-end, a positive third group including a unit moving toward object-side during zooming from wide-end to telephoto-end, a negative fourth group moving during zooming and focusing, and a rear group. Focal lengths of the first group and the zoom lens at wide-end, a movement amount of a unit moving by largest amount during zooming toward telephoto-end in the second group, a largest value of position change between wide-end and telephoto-end of units moving toward an object side during zooming from wide-end to telephoto-end, refractive index for d-line of a positive lens closest to image-side in the first group, and average refractive index for d-line of positive lenses of the first group other than the positive lens are appropriately set.

A finite conjugate lens assembly with modular interchangeable components includes a zooming component that includes three independently movable lens groups that are disposed within the lens assembly between a pair of static lens groups. The lens assembly exhibits an etendue of between 0.95 and 4.65 mm.sup.2sr.

A lens attachment module is configured for coupling with a zoom module of a finite conjugate optical assembly. The lens attachment module includes a lens assembly that has a positive focal length, and exhibits a pupil size of between 16 and 25 mm and a pupil depth greater than 50 mm.

A rear adapter module for a finite conjugate optical assembly and camera is configured to couple with a core zoom module. A lens assembly of the rear adapter module includes three or more lens elements and has a positive focal length. The lens assembly exhibits a pupil size of between 16 and 25 mm and a pupil depth greater than 50 mm.

A zoom lens includes in order from an object side: a positive first lens unit not moving for zooming; a negative second lens unit moving for zooming; a negative third lens unit moving for zooming; an intermediate lens group including a lens unit and moving for zooming; and a rear lens group including a lens unit, a lens unit, closest to an object of the zoom lens, not moving for zooming, an aperture stop being placed on a side of the object to or in the rear lens group, a distances between each pair of adjacent lens units changes for zooming, and a distance between the second and third lens units at a wide angle end, a distance between the second and third lens units at a telephoto end, and a maximum distance between the second and third lens units in a certain zoom range are appropriately set.

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.