A variable magnification optical system comprising, in order from an object side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, and a rear lens group having negative refractive power; upon varying a magnification from a wide angle end state to a tele photo end state, a distance between the first lens group and the second lens group being varied, a distance between the second lens group and the third lens group being varied, and a distance between the third lens group and the rear lens group being varied; the third lens group or the rear lens group comprising a focusing lens group which is moved upon carrying out focusing from an infinitely distant object to a closely distant object; and predetermined conditional expression(s) being satisfied, thereby various aberrations being corrected superbly.

A zoom optical system comprises, in order from an object: a front lens group (GFS) having a positive refractive power; an M1 lens group (GM1) having a negative refractive power; an M2 lens group (GM2) having a positive refractive power; an RN lens group (GRN) having a negative refractive power; and a subsequent lens group (GRS). Upon zooming, the distance between the front lens group (GFS) and the M1 lens group (GM1) changes, the distance between the M1 lens group (GM1) and the M2 lens group (GM2) changes, and the distance between the M2 lens group (GM2) and the RN lens group (GRN) changes. Upon focusing from an infinite distant object to a short distant object, the RN lens group (GRN) moves.

A variable magnification optical system comprising, in order from an object side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, and a rear lens group having negative refractive power; upon varying a magnification from a wide angle end state to a tele photo end state, a distance between the first lens group and the second lens group being varied, a distance between the second lens group and the third lens group being varied, and a distance between the third lens group and the rear lens group being varied; the third lens group or the rear lens group comprising a focusing lens group which is moved upon carrying out focusing from an infinitely distant object to a closely distant object; and predetermined conditional expression(s) being satisfied, thereby various aberrations being corrected superbly.

A zoom optical system (ZL) comprises, in order from an object: a first lens group (G1) having a positive refractive power; a second lens group (G2) having a negative refractive power; a third lens group (G3) having a positive refractive power; and a subsequent lens group (GR), wherein upon zooming, a distance between the first lens group (G1) and the second lens group (G2) changes, a distance between the second lens group (G2) and the third lens group (G3) changes, and a distance between the third lens group (G3) and the subsequent lens group (GR) changes, the subsequent lens group (GR) comprises a focusing lens group that moves upon focusing, and the second lens group (G2) comprises a partial group that satisfies following conditional expressions, 1.40<fvr/f2<2.30, 1.80<f1/fw<3.50 where fvr: a focal length of the partial group, f2: a focal length of the second lens group (G2), f1: a focal length of the first lens group (G1), and fw: a focal length of the zoom optical system (ZL) in a wide-angle end state.

In an optical system according to each exemplary embodiment, an interval between adjacent lens units changes in focusing from an infinite-distance object to a close-distance object, and a first in-focus state in which β=−1.2 is obtained can be caused, where β is a lateral magnification of an entire system. The optical system according to each exemplary embodiment includes a plurality of focus lens units, and out of a focus lens unit having a largest absolute value of a focus sensitivity and a focus lens unit having a second largest absolute value of a focus sensitivity in a state in which focus is put on an infinite-distance object, a focus lens unit disposed on an object side is a lens unit LA, and a focus lens unit disposed on an image side is a lens unit LB. A partial optical system LC including all lenses disposed on the image side of the lens unit LB has negative refractive power. The partial optical system LC satisfies a predetermined conditional expression.

A zoom lens includes a positive first lens group, a negative second lens group, a positive third lens group, a positive fourth lens group, and a fifth lens group in order from an object side. In a case of zooming, an interval with an adjacent lens group is changed. The third lens group includes two positive lenses consecutively arranged in order from a side closest to the object side to an image side. The fifth lens group consists of a negative meniscus lens having a concave surface toward the object side and a positive lens having a convex surface toward the object side in order from the object side to the image side.

A zoom optical system (ZL) comprises, in order from an object: a first lens group (G1) having a positive refractive power; a second lens group (G2) having a negative refractive power; a third lens group (G3) having a positive refractive power; and a subsequent lens group (GR), wherein upon zooming, a distance between the first lens group (G1) and the second lens group (G2) changes, a distance between the second lens group (G2) and the third lens group (G3) changes, and a distance between the third lens group (G3) and the subsequent lens group (GR) changes, the subsequent lens group (GR) comprises a focusing lens group that moves upon focusing, and the second lens group (G2) comprises a partial group that satisfies following conditional expressions, 1.40<fvr/f2<2.30, 1.80<f1/fw<3.50 where fvr: a focal length of the partial group, f2: a focal length of the second lens group (G2), f1: a focal length of the first lens group (G1), and fw: a focal length of the zoom optical system (ZL) in a wide-angle end state.

A variable magnification optical system comprising a plurality of lens groups which includes a first negative lens group having negative refractive power, a second negative lens group disposed at a more image side than the first negative lens group and having negative refractive power, a third negative lens group disposed at a more image side than the second negative lens group and having negative refractive power; upon varying a magnification, distances between adjacent lens groups being varied; the first negative lens group being movable to include a component in a direction perpendicular to the optical axis as a vibration reduction lens group; the second negative lens group being moved along the optical axis upon carrying out focusing; and the predetermined conditional expression (s) being satisfied. The variable magnification optical system can attain a high optical performance and be made in small in size.

A zoom optical system (ZL) comprises, in order from an object: a first lens group (G1) having a positive refractive power; a second lens group (G2) having a negative refractive power; a third lens group (G3) having a positive refractive power; and a subsequent lens group (GR), wherein upon zooming, a distance between the first lens group (G1) and the second lens group (G2) changes, a distance between the second lens group (G2) and the third lens group (G3) changes, and a distance between the third lens group (G3) and the subsequent lens group (GR) changes, the subsequent lens group (GR) comprises a focusing lens group that moves upon focusing, and the second lens group (G2) comprises a partial group that satisfies following conditional expressions, 1.40<fvr/f2<2.30, 1.80<f1/fw<3.50 where fvr: a focal length of the partial group, f2: a focal length of the second lens group (G2), f1: a focal length of the first lens group (G1), and fw: a focal length of the zoom optical system (ZL) in a wide-angle end state.

A variable magnification optical system comprising, in order from an object side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, and a rear lens group having negative refractive power; upon varying a magnification from a wide angle end state to a tele photo end state, a distance between the first lens group and the second lens group being varied, a distance between the second lens group and the third lens group being varied, and a distance between the third lens group and the rear lens group being varied; the third lens group or the rear lens group comprising a focusing lens group which is moved upon carrying out focusing from an infinitely distant object to a closely distant object; and predetermined conditional expression(s) being satisfied, thereby various aberrations being corrected superbly.