A zoom optical system comprises, in order from an object: a first lens group (G1) having positive refractive power; a second lens group (G2) having negative refractive power; and a subsequent group (GR) including at least one lens group. Upon zooming, distances between the first lens group (G1) and the second lens group (G2) and between the second lens group (G2) and the subsequent group (GR) change. The subsequent group (GR) comprises a focusing group (Gfc) having negative refractive power for focusing. The first lens group (G1) comprises a 1-1st lens that has positive refractive power and is disposed closest to the object. A following conditional expression is satisfied:
0.20<f1/fR<0.85 where, f1 denotes a focal length of the first lens group, and fR denotes a focal length of a lens component, in the subsequent group, closest to an image surface.

Provided is a zoom lens consisting of, in order from an object side to an image side: a positive front lens unit configured not to move for zooming; a plurality of magnification-varying lens units including two magnification-varying lens units having negative refractive powers configured to move for zooming; and a positive rear lens unit configured not to move for zooming, in which a focal length of the front lens unit, a focal length of a magnification-varying lens unit having a negative refractive power and arranged closest to the object side in the plurality of magnification-varying lens units, a focal length of a magnification-varying lens unit having a negative refractive power and arranged closest to the image side in the plurality of magnification-varying lens units, and a focal length of the rear lens unit are suitably set.

Provided is a zoom lens consisting of, in order from an object side to an image side: a positive front lens unit configured not to move for zooming; a plurality of magnification-varying lens units including two magnification-varying lens units having negative refractive powers configured to move for zooming; and a positive rear lens unit configured not to move for zooming, in which a focal length of the front lens unit, a focal length of a magnification-varying lens unit having a negative refractive power and arranged closest to the object side in the plurality of magnification-varying lens units, a focal length of a magnification-varying lens unit having a negative refractive power and arranged closest to the image side in the plurality of magnification-varying lens units, and a focal length of the rear lens unit are suitably set.

A zoom lens includes in order from an object side, a positive first unit, one or two second units including a negative lens unit closest to the image side, and monotonously moved to the image side for zooming to a telephoto end, one or two third units including a negative lens unit closest to the object side, and moved for zooming, and a positive fourth unit disposed closest to the image side, in which the first unit includes, in order from the object side, a negative subunit, a positive subunit moved for focusing, and a positive subunit, and a focal length of the first unit, a composite focal length at the telephoto end of the second unit, a maximum moving amount for zooming of the lens unit included in the second unit, and a maximum Abbe number of the negative lens included in the second unit are properly set.

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 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 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.

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.

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 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.