A lens 1 has unevenness within an optical effective diameter D of an optical surface 2, an arithmetic mean roughness Ra within the optical effective diameter D of the optical surface 2 is 20 nm or more and 50 nm or less, and an average value of widths W of protrusion portions 3 of the unevenness on an average line C2 of a roughness curve C1 of the optical surface 2 is 1/200 or more and 1/50 or less of the optical effective diameter D of the optical surface 2. The lens 1 is suitably used as a lens that composes a zoom lens or an imaging lens.

A lens 1 has unevenness within an optical effective diameter D of an optical surface 2, an arithmetic mean roughness Ra within the optical effective diameter D of the optical surface 2 is 20 nm or more and 50 nm or less, and an average value of widths W of protrusion portions 3 of the unevenness on an average line C2 of a roughness curve C1 of the optical surface 2 is 1/200 or more and 1/50 or less of the optical effective diameter D of the optical surface 2. The lens 1 is suitably used as a lens that composes a zoom lens or an imaging lens.

The zoom lens includes a positive first lens group, a negative second lens group, a positive third lens group, a negative fourth lens group, a negative fifth lens group, and a positive sixth lens group in order from an object side. All distances between adjacent lens groups change during zooming. The first lens group consists of a negative lens, a positive lens, and a positive lens in order from the object side. Only the fourth lens group moves to an image side during focusing from a long range to a short range. Conditional Expression is related to lateral magnification of the fourth lens group and a lateral magnification of the sixth lens group is satisfied.

A reduction optical system disposed on an image side of a main optical system, a composite focal length of the main optical system and the reduction optical system being shorter than a focal length of the main optical system, includes a first lens element disposed closest to an object side and having a positive refractive power, a second lens element disposed closest to an image side and having a positive refractive power, and a positive lens and a negative lens disposed between the first lens element and the second lens element.

A reduction optical system disposed on an image side of a main optical system, a composite focal length of the main optical system and the reduction optical system being shorter than a focal length of the main optical system, includes a first lens element disposed closest to an object side and having a positive refractive power, a second lens element disposed closest to an image side and having a positive refractive power, and a positive lens and a negative lens disposed between the first lens element and the second lens element.

An optical system consists of a front lens unit having a positive or negative refractive power, a diaphragm, and a rear lens unit having a positive refractive power, which are arranged in this order from an object side to an image side. The front lens unit includes an aspherical lens that has a positive refractive power on an optical axis, and is disposed closest to an object. The aspherical lens has an aspherical surface on the object side in which an off-axis radius of curvature is larger than an on-axis radius of curvature. A predetermined condition is satisfied.

An optical system consists of a front lens unit having a positive or negative refractive power, a diaphragm, and a rear lens unit having a positive refractive power, which are arranged in this order from an object side to an image side. The front lens unit includes an aspherical lens that has a positive refractive power on an optical axis, and is disposed closest to an object. The aspherical lens has an aspherical surface on the object side in which an off-axis radius of curvature is larger than an on-axis radius of curvature. A predetermined condition is satisfied.

A zoom lens includes: a first lens group having negative refractive power and a subsequent group in order from an object side to an image side. The subsequent group includes, in order from an object side to an image side, a Gp1 group including one or more lens groups and having positive refractive power as a whole, a Gn1 group including one or more lens groups and having negative refractive power as a whole, a Gp2 group including one or more lens groups and having positive refractive power as a whole, and a Gn2 group including one or more lens groups and having negative refractive power as a whole. An aperture diaphragm is disposed closer to an object side than the Gp2 group, an interval between adjacent lens groups changes at least during one of zooming and focusing, and a predetermined expression is satisfied.

A zoom lens includes: a first lens group having negative refractive power and a subsequent group in order from an object side to an image side. The subsequent group includes, in order from an object side to an image side, a Gp1 group including one or more lens groups and having positive refractive power as a whole, a Gn1 group including one or more lens groups and having negative refractive power as a whole, a Gp2 group including one or more lens groups and having positive refractive power as a whole, and a Gn2 group including one or more lens groups and having negative refractive power as a whole. An aperture diaphragm is disposed closer to an object side than the Gp2 group, an interval between adjacent lens groups changes at least during one of zooming and focusing, and a predetermined expression is satisfied.

An optical system is constituted of a first lens unit having a positive refractive power, a second lens unit having a positive refractive power and moving when focusing is performed, and a third lens unit which are arranged in this order from an object side to an image side, and distances between neighboring lens units are changed when focusing is performed. In the optical system, a back focus, arrangement of the second lens unit, and the like are appropriately set.