Provided is a zoom lens including a plurality of lens units, in which an interval between each pair of adjacent lens units is changed for zooming. The plurality of lens units consist of, in order from an object side to an image side: a first lens unit having a negative refractive power; a second lens unit having a positive refractive power; and a rear lens group including at least two lens units. The first lens unit and the second lens unit are configured to move during zooming. The first lens unit includes, in order from the object side to the image side, a negative lens G1, a negative lens G2, and a negative lens G3.

An optical imaging system includes a first lens group, a second lens group, and a third lens group, sequentially arranged from an object side, wherein the first lens group includes two lenses having negative and positive refractive power, the second lens group includes a plurality of lenses, and the third lens group includes two lenses having negative and positive refractive power.

The zoom lens according to the present invention includes a plurality of lens units consisting of front and rear groups having negative and positive refractive powers at a wide angle end (WAE), respectively. An interval between front and rear groups on an optical axis is longest among all intervals between adjacent ones of plurality of lens units at WAE. The rear group is disposed at an image side of front group and includes a plurality of lens units including a negative lens unit LN (LULN) disposed closest to image side. The LULN includes negative and positive lenses disposed closest to object and image sides in LULN, respectively. A focal length of LULN, a focal length of zoom lens at WAE, a distance on optical axis between a lens surface closest to object side and that closest to image side in LULN, and a back focus at WAE are appropriately set.

An optical imaging system includes a first lens group, a second lens group, and a third lens group, sequentially arranged from an object side, wherein the first lens group includes two lenses having negative and positive refractive power, the second lens group includes a plurality of lenses, and the third lens group includes two lenses having negative and positive refractive power.

A zoom optical system consists of a first lens group having negative refractive power, a second lens group having positive refractive power, and a rear lens group which are disposed in order from an object. The rear lens group comprises a last lens group and an F lens group in order from a side closest to an image. Lens groups forming the first lens group, the second lens group, and the rear lens group are configured in such a manner that, upon zooming, the respective lens groups move and a distance between the lens groups adjacent to each other changes. At least a part of the F lens group is configured to move upon focusing. Further, the following conditional expression is satisfied.
0.220<f1/fE<0.280
where f1: a focal length of the first lens group, and fE: a focal length of the last lens group.

A zoom optical system consists of a first lens group having negative refractive power, a second lens group having positive refractive power, and a rear lens group which are disposed in order from an object. The rear lens group comprises a last lens group and an F lens group in order from a side closest to an image. Lens groups forming the first lens group, the second lens group, and the rear lens group are configured in such a manner that, upon zooming, the respective lens groups move and a distance between the lens groups adjacent to each other changes. At least a part of the F lens group is configured to move upon focusing. Further, the following conditional expression is satisfied.

0.220<f1/fE<0.280 where f1: a focal length of the first lens group, and fE: a focal length of the last lens group

An optical imaging system includes a first lens group, a second lens group, and a third lens group, sequentially arranged from an object side, wherein the first lens group includes two lenses having negative and positive refractive power, the second lens group includes a plurality of lenses, and the third lens group includes two lenses having negative and positive refractive power.

A variable magnification optical system consists of, in order from an object side to an image side, a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a subsequent group including one or more lens groups. During changing magnification, the first lens group moves, and spacings between all adjacent lens groups change. One lens group included in the subsequent group is a focusing lens group that moves along an optical axis during focusing. The variable magnification optical system satisfies a predetermined conditional expression.

A zoom lens consists of, in order from an object side to an image side, a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and a rear group including one or more lens units. Each distance between adjacent lens units changes during zooming. The rear group includes a focus lens unit having a positive refractive power that moves from the image side to the object side during focusing from an infinite distance object to a close distance object. A lens closest to an object in the focus lens unit has a shape with a concave surface on the object side. The following inequalities are satisfied.
1.20<fLP/fL2<3.20
3.00<fL1/fL2<0.85
fLP represents a focal length of the focus lens unit, fL1 represents a focal length of the first lens unit, and fL2 represents a focal length of the second lens unit.

An imaging optical system includes a plurality of lens units. Each distance between adjacent lens units among the plurality of lens units changes during zooming. The plurality of lens units include a first lens unit with negative refractive power and a second lens unit with positive refractive power disposed closer to an image plane than the first lens unit, and a first transmissive reflective surface and a second transmissive reflective surface disposed closer to the image plane than the first transmissive reflective surface.