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

Provided is a zoom lens including: a lens unit Ln1 having a negative refractive power; a lens unit Ln2 having a negative refractive power; a lens unit Lp1 having a positive refractive power; and a rear lens group including one or more lens units, the lens unit Ln1, the lens unit Ln2, the lens unit Lp1, and the rear lens group being successively arranged in order from an object side to an image side, in which the lens unit Ln1 and the lens unit Lp1 are moved along the same locus during zooming, and in which the lens unit Ln2 is moved toward the object side during focusing from infinity to proximity.

The disclosure provides a zoom lens group, which sequentially includes, from an object side to an image side along an optical axis: a first lens group with negative refractive power, including a first lens and a second lens, wherein the first lens has negative refractive power, and an object-side surface thereof is a concave surface; a second lens group with positive refractive power; a third lens group with positive refractive power; and a fourth lens group with negative refractive power. A spacing distance of the first lens group and the second lens group on an optical axis, a spacing distance of the second lens group and the third lens group on the optical axis and a spacing distance of the third lens group and the fourth lens group on the optical axis are changed to switch the zoom lens group from a telephoto state to a wide-angle state.

The disclosure discloses a zoom lens group, which sequentially includes from an object side to an image side along an optical axis: a first lens group having a negative refractive power; a second lens group having a positive refractive power; a third lens group having a refractive power and having a fifth lens and a sixth lens, wherein the fifth lens and the sixth lens are formed into a cemented lens; and a fourth lens group having a refractive power. By adjusting a spacing distance on the optical axis between the first lens group and the second lens group, a spacing distance on the optical axis between the second lens group and the third lens group and a spacing distance on the optical axis between the third lens group and the fourth lens group, the zoom lens group is switched from a long-focus state to a wide-angle state.

The disclosure discloses a zoom lens group, which sequentially includes from an object side to an image side along an optical axis: a first lens group having a negative refractive power; a second lens group having a positive refractive power; a third lens group having a refractive power and having a fifth lens and a sixth lens, wherein the fifth lens and the sixth lens are formed into a cemented lens; and a fourth lens group having a refractive power. By adjusting a spacing distance on the optical axis between the first lens group and the second lens group, a spacing distance on the optical axis between the second lens group and the third lens group and a spacing distance on the optical axis between the third lens group and the fourth lens group, the zoom lens group is switched from a long-focus state to a wide-angle state.

The disclosure discloses a zoom lens group, which sequentially includes, from an object side to an image side along an optical axis: a first lens group with negative refractive power, including a first lens and a second lens, wherein the first lens has negative refractive power, and an object-side surface thereof is a concave surface; a second lens group with positive refractive power; a third lens group with positive refractive power; and a fourth lens group with negative refractive power. A spacing distance of the first lens group and the second lens group on an optical axis, a spacing distance of the second lens group and the third lens group on the optical axis and a spacing distance of the third lens group and the fourth lens group on the optical axis are changed to switch the zoom lens group from a telephoto state to a wide-angle state.

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 imaging optical system includes: a first lens group having negative power; a second lens group having positive power; a third lens group having negative power; and a fourth lens group having power, which are arranged in this order such that the first lens group is located closest to an object and the fourth lens group is located closest to an optical image. The first lens group includes: a first negative lens; a second negative lens; and a third negative lens which is a meniscus lens having negative power and a convex surface facing the optical image, which are arranged in this order such that the first negative lens is located closest to the object and the third negative lens is located closest to the optical image. During focusing from an infinity focus point toward a close focus point, the third lens group moves along an optical axis.

An ocular lens includes from an object side: a first lens group having negative refracting power, and a second lens group having positive refracting power. An object-side focal plane of the second lens group is positioned between the first lens group and the second lens group. The first lens group includes, from the object side: a meniscus first A lens component whose convex surface is directed toward the object side, and a first B lens component having negative refracting power. The second lens group includes, in a position closest to the object side, a meniscus second A lens component whose concave surface is directed toward the object side, and satisfies conditional expressions.