A variable magnification optical system includes, in order from the object side along the optical path, a first group that has a positive power, a second group that has a positive power, a third group that has a negative power, a stop, a fourth group that has a positive power, and a fifth group that has a positive power. The first group includes two mirrors. An intermediate image is formed in the optical path between the first group and the second group. The second group, the third group, and the fourth group are refractive optical systems. During changing magnification, the two mirrors of the first group, the second group, the stop, and the fifth group are immovable, the third group moves to the image side, and the fourth group moves to the object side.

The variable magnification optical system consists of, in order from an object side to an image side, a first lens group that has a positive refractive power, a plurality of lens groups, and a final lens group that has a positive refractive power. During changing magnification, a spacing between the first lens group and the lens group closest to the object side among the plurality of lens groups changes, all spacings between adjacent lens groups in the plurality of lens groups change, and a spacing between the lens group closest to the image side and the final lens group among the plurality of lens groups changes.

An optical system (ZL(1)) comprises a plurality of lens groups including a first focusing lens group (G2) and a second focusing lens group (G4) that are disposed side by side on an optical axis, and the second focusing lens group (G4) is disposed at a position closer to an image surface than the first focusing lens group (G2). The first focusing lens group (G2) has positive refractive power, and moves toward an object along the optical axis from focusing on an infinite-distance object to focusing on a short-distance object. The second focusing lens group (G4) moves toward the image surface along the optical axis from focusing on the infinite-distance object to focusing on the short-distance object. The optical system (ZL(1)) satisfies the following conditional expression. −020<βF1/βF2<0.50 where βF1 is the lateral magnification of the first focusing lens group at the time of focusing on the infinite-distance object, and βF2 is the lateral magnification of the second focusing lens group at the time of focusing on the infinite-distance object.

An optical system (ZL(1)) comprises a plurality of lens groups including a first focusing lens group (G2) and a second focusing lens group (G4) that are disposed side by side on an optical axis, and the second focusing lens group (G4) is disposed at a position closer to an image surface than the first focusing lens group (G2). The first focusing lens group (G2) has positive refractive power, and moves toward an object along the optical axis from focusing on an infinite-distance object to focusing on a short-distance object. The second focusing lens group (G4) moves toward the image surface along the optical axis from focusing on the infinite-distance object to focusing on the short-distance object. The optical system (ZL(1)) satisfies the following conditional expression. −020<βF1/βF2<0.50 where βF1 is the lateral magnification of the first focusing lens group at the time of focusing on the infinite-distance object, and βF2 is the lateral magnification of the second focusing lens group at the time of focusing on the infinite-distance object.

The present disclosure is directed to an optical system internally having an intermediate imaging position that is conjugated to a magnification conjugate point on a magnification side and a reduction conjugate point on a reduction side, respectively, the optical system including: a magnification optical system having a plurality of lens elements, positioned on the magnification side with respect to the intermediate imaging position; and a relay optical system having a plurality of lens elements, positioned on the reduction side with respect to the intermediate imaging position. The magnification optical system has a first lens element and a second lens element in this order from the magnification side, and the second lens element has a positive power. The optical system satisfies the following condition (1): 23<|f2/fw|<1000 . . . (1), where, f2 is a focal length of the second lens element, and fw is a focal length of the entire optical system at the wide-angle end.

The zoom lens consists of, in order from an object side: a first lens group that has a positive refractive power; a second lens group that has a positive refractive power; a third lens group that has a negative refractive power; a fourth lens group; and a fifth lens group that has a positive refractive power. The first lens group and the fifth lens group remain stationary with respect to an image plane during zooming. The second lens group, the third lens group, and the fourth lens group are moved by changing distances between the lens groups and adjacent groups in a direction of an optical axis during zooming, and are positioned to be closer to the image side at a telephoto end than at a wide-angle end. Conditional Expression (1) is satisfied.
0.8<pr1/f1<2.6(1).

An optical system internally has an intermediate imaging position that is conjugated to a magnification conjugate point on a magnification side and a reduction conjugate point on a reduction side, respectively. The optical system includes a magnification optical system having a first lens element and a second lens element positioned on the magnification side with respect to the intermediate imaging position; and a relay optical system having a plurality of lens elements, positioned on the reduction side with respect to the intermediate imaging position. The first lens element and the second lens element are positioned in this order from the magnification side, and the second lens element has a positive power. The optical system satisfies: 23<|f2/fw|<1000, wherein f2 is a focal length of the second lens element, and fw is a focal length of an entirety of the optical system at a wide-angle end.

A variable magnification optical system includes, in order from the object side along the optical path, a first group that has a positive power, a second group that has a positive power, a third group that has a negative power, a stop, a fourth group that has a positive power, and a fifth group that has a positive power. The first group includes two mirrors. An intermediate image is formed in the optical path between the first group and the second group. The second group, the third group, and the fourth group are refractive optical systems. During changing magnification, the two mirrors of the first group, the second group, the stop, and the fifth group are immovable, the third group moves to the image side, and the fourth group moves to the object side.

The zoom lens consists of, in order from an object side: a first lens group that has a positive refractive power; a second lens group that has a positive refractive power; a third lens group that has a negative refractive power; a fourth lens group that has a positive refractive power; and a fifth lens group that has a positive refractive power. The first lens group and the fifth lens group remain stationary with respect to an image plane during zooming. The second lens group, the third lens group, and the fourth lens group are moved by changing distances between the lens groups and adjacent groups in a direction of an optical axis during zooming, and are positioned to be closer to the image side at a telephoto end than at a wide-angle end. A stop is provided between the fourth lens group and the fifth lens group. In addition, Conditional Expression (1) is satisfied.
0.1<fw/f4<0.5(1)

The zoom lens consists of, in order from the object side, a first lens group that has a positive refractive power and remains stationary during zooming, a plurality of movable lens groups that move during zooming, and a final lens group that has a positive refractive power and remains stationary during zooming. The first lens group consists of, in order from the object side, a first lens group front group that has a negative refractive power and remains stationary during focusing, a first lens group intermediate group that has a positive refractive power and moves during focusing, and a first lens group rear group that has a positive refractive power. The first lens group front group has, successively in order from a position closest to the object side, a negative meniscus lens that is concave toward the image side and a negative lens.