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<f2/TTL<−0.15, where TTL is an optical total length at the telephoto end and f2 is a focal length of the second lens group.

A zoom lens consists of, in order from the object side, a positive first lens group that is fixed during magnification change, at least three movable lens groups that are moved during magnification change, and a positive end lens group that is disposed at the most image side and is fixed during magnification change. The at least three movable lens groups include, in order from the object side, a positive lens group, a negative lens group, and a negative lens group. The first lens group includes at least two negative lenses, where the most object-side negative lens has a meniscus shape with the convex surface toward the object side, and a first-n lens, which is at least one negative lens of the rest of the negative lenses of the first lens group, satisfies given condition expressions (1) and (2).

A zoom lens system according to the present disclosure includes, in order from an object side to an image plane side, a first lens group having positive optical power; a second lens group having negative optical power; a third lens group having positive optical power; and a subsequent lens group including a fourth lens group, a fifth lens group, and a sixth lens group. The first lens group comprises, in order from the object side, a first lens element having negative optical power; a second lens element having positive optical power; a third lens element having positive optical power; and a fourth lens element having positive optical power. The fifth lens group in the subsequent lens group has negative optical power. The first lens group is fixed with respect to the image plane in zooming from a wide-end to a tele-end upon image shooting.

An imaging optical system includes: a front group having positive power; an aperture stop; a single lens Fn arranged adjacent to the aperture stop and having negative power; and a rear group having power. The front group includes: a first lens having positive power; a second lens having negative power; and a lens LG1R having positive power. The rear group includes a lens LGnR having negative power and located closest to the image. While focusing to make a transition from an infinity in-focus state to a close-object in-focus state, neither the front group nor the rear group moves but the single lens Fn moves along an optical axis toward the image. The imaging optical system satisfies the inequality: 0.38<fLG1R/fG1<1.75, where fG1 is a focal length of the front group and fLG1R is a focal length of the lens LG1R.

A dome camera includes a camera body rotatable and including a lens system and an imaging device, a correction optical system having a curved shape, and a dome cover covering the camera body and the correction optical system. The correction optical system performs at least any one of tilt, decenter, and rotation in accordance with a rotation angle of the camera body.

A zoom lens includes, in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit having a negative power, and a rear unit having a positive refractive power as a whole and including one or more lens units. A distance between adjacent lens units changes during zooming. The first lens unit includes a first subunit having a positive refractive power and a second subunit disposed on the image side of the first subunit. The first subunit includes a first positive lens having the smallest absolute value of a focal length among lenses included in the first subunit. The second subunit includes a second positive lens and a first negative lens having the smallest absolute value of a focal length among negative lenses included in the second subunit. A predetermined condition is satisfied.

The zoom lens consists of a first optical system including a lens at a position closest to the magnification side and a second optical system forming an intermediate image in order from the magnification side. The first optical system reforms the intermediate image on a magnification side imaging plane. The second optical system includes a lens group including an aperture stop, having a negative refractive power, and moving during zooming. The zoom lens satisfies a conditional expression: 0.1<f2w/fAp<2.1, where fAp is a focal length of the lens group having the aperture stop and f2w is a focal length of the second optical system at a wide angle end.

An optical system (LS) has a lens (L11) that satisfies the following conditional expressions.

−0.010<ndLZ−(2.015−0.0068×νdLZ)

50.00<νdLZ<65.00 0.545<θgFLZ

−0.010<θgFLZ−(0.6418−0.00168×νdLZ) where ndLZ is the refractive index to the d line of the lens, νdLZ is the Abbe number with respect to the d line of the lens, and θgFLZ is the partial dispersion ratio of the lens.

This optical system (LS) has an aperture diaphragm (S) and a negative lens (L4) disposed closer to an object side than the aperture diaphragm (S) and satisfies the following conditional expression.

−0.010<ndN1−(2.015−0.0068×νdN1),

50.00<νdN1<65.00, 0.545<θgFN1,

−0.010<θgFN1−(0.6418−0.00168×νdN1).

Where, ndN1 is a refractive index of the negative lens with respect to a d-line, vdN1 is an Abbe number of the negative lens based on the d-line, and θgFN1 is a partial dispersion ratio of the negative lens.

A lens system provides a zoom function (variable magnification) in a low profile camera (lens system height less than or equal to 6 mm), which may be in a cellular phone. The lens system includes at least three movable lens groups that are movable along a common optical axis. Each of the three movable lens groups is coupled to a corresponding actuator. Responsive to a request for a change in focal length or magnification, a controller sends a corresponding signal to each of the actuators that move the corresponding lens group by a corresponding distance in a corresponding direction. The various movable lens groups may be moved by different distances and in different directions of movement. An f-number of the lens system is less than f/3.0. Focusing of an image cast onto an image sensor is accomplished by adjusting the position along the optical axis of one of the movable lens groups.