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

The variable magnification optical system consists of a front group, a middle group, and a rear group, in order from an object side. The front group consists of two or fewer lens groups and has a negative refractive power. The middle group includes only one lens group that has a positive refractive power as a lens group. The rear group consists of three or less lens groups. An aperture stop is disposed between a lens surface closest to an image side in the front group and a lens surface closest to the object side in the rear group. The front group includes at least three negative lenses and at least one positive lens. A negative meniscus lens convex toward the object side is disposed closest to the object side in the front group. The variable magnification optical system satisfies predetermined conditional expressions.

A zoom lens comprising in order from an object side, a first lens unit having a negative refractive power, a second lens unit having a negative refractive power, a lens unit having a positive refractive power, and a rearmost lens unit having a negative refractive power, and the rearmost lens unit is positioned nearest to an image in the plurality of lens units, and at the time of zooming, distances between the lens units in the plurality of lens units change. Moreover, an image pickup apparatus includes the zoom lens, and an image pickup element having an image pickup surface.

A zoom lens includes, in order from an object side to an image side, a first lens unit having a negative refractive power, and a rear unit having a positive refractive power as a whole. A distance between the first lens unit and the rear unit is changed during zooming. The rear unit includes a subunit that is moved in a direction having a component of a direction orthogonal to an optical axis during image stabilization. The first lens unit includes, in order from the object side to the image side, three or more negative lenses. A predetermined condition is satisfied.

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 lens B0 includes a first lens unit B1 having negative refractive, a second lens unit B2 having positive refractive power, and a third lens unit B3 having negative refractive power in order from an object side to an image side. The first lens unit B1 moves during zooming. The first lens unit B1 includes a negative lens G1 disposed closest to the object side and at least one positive lens. Lenses included in the second lens unit B2 all have positive refractive power. The number of lenses included in the third lens unit B3 is two or less. The third lens unit B3 moves toward the image side during focusing from infinity to close range.

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.

A zoom lens system includes multiple lens groups and an aperture stop. The multiple lens groups consist of: 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 negative power. The aperture stop is disposed between the first and second lens groups. The zoom lens system satisfies 0.5<fw/BFw <1.5, where fw is a focal length of the zoom lens system at a wide-angle end and BFw is a back focus of the zoom lens system at the wide-angle end.

An imaging optical system includes, in order from an object side to an image side, a first lens group having negative optical power, a second lens group having positive optical power, a third lens group having negative optical power, and a fourth lens group with negative optical power. A lens disposed closest to the object side in the second lens group has a concave surface directed toward the object side, and a lens disposed closest to the object side in the fourth lens group has positive optical power. Each distance between the lens groups changes when zooming from a wide-angle end to a telephoto end on photographing.