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 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.

Provided is a zoom lens including, in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, and a fourth lens unit having a negative refractive power. In the zoom lens, an interval between each pair of adjacent lens units is changed during zooming, and the first lens unit is configured not to move for zooming. Further, a total length DT of the zoom lens at a telephoto end, a focal length fT of the zoom lens at the telephoto end, a distance BW of a back focus at a wide-angle end, a total length DW of the zoom lens at the wide-angle end, and a focal length f3 of the third lens unit are each appropriately set.

A first lens group (G1) having positive refractive power, a second lens group (G2) having negative refractive power, a third lens group (G3) having positive refractive power, a fourth lens group (G4) having negative refractive power, and a fifth lens group (G5) having positive refractive power are arranged in order from an object, and zooming is performed by changing distances between each lens group, and the first lens group (G1) is composed of three or more lenses, the fourth lens group (G4) is composed of two or less lenses, and the fifth lens group (G5) is composed of two or less lenses and moves to an image surface side upon zooming from a wide angle end state to a telephoto end state, and the following conditional expression (1) is satisfied.

8.40<f1/(−f2)  (1) where, f1 denotes a focal length of the first lens group (G1), and f2 denotes a focal length of the second lens group (G2).

A variable magnification optical system comprising a plurality of lens groups which includes a first positive lens group disposed at a most object side and having positive refractive power, a first negative lens group disposed at an image side of the first positive lens group and having negative refractive power, and a second negative lens group disposed at a more image side than the first 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 first negative lens group further including a lens that satisfies predetermined conditional expression(s), thereby various aberrations being corrected superbly, and vibration reduction lens group being made small in size.

An optical system includes a front lens group and a rear lens group that are disposed in order from an object side to an image side of the optical system, the front lens group having a positive refractive power and the rear lens group having a negative refractive power. The rear lens group consists of a lens unit Ln1 that is arranged to move towards the image side when focusing and that has a negative refractive power, and a lens unit Ln2 that is disposed closer to the image side than the lens unit Ln1 and that has a negative refractive power. The front lens group includes a lens unit Lpf arranged to move during focusing. The rear lens group satisfies a predetermined conditional expression.

A zoom optical system (ZL) comprises: a first lens group (G1) disposed closest to an object and having a positive refractive power; an aperture stop (S) disposed closer to an image than the first lens group (G1); a positive lens component disposed so as to oppose the image side of the aperture stop (S); and a lens group (G3) having the positive lens component, wherein a distance between the first lens group (G1) and the lens group (G3) having the positive lens component changes during zooming, at least one lens surface of the positive lens component has an aspherical surface, and the following conditional expression,

0.40<fp/fGp<3.60

is satisfied,
where fp: a focal length of the positive lens component, and fGp: a focal length of the lens group (G3) having the positive lens component.

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.

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 negative refractive power, a middle group that includes one or more lens groups, and a final lens group. The middle group has a positive refractive power as a whole throughout an entire zoom range. During zooming, a spacing between the first lens group and the second lens group changes, a spacing between the second lens group and the middle group changes, and a spacing between the middle group and the final lens group changes. The zoom lens satisfies predetermined conditional expressions.

A zoom lens ZL includes: a first lens unit L1 having a positive refractive power, a second lens unit L2 having a negative refractive power, and a third lens unit L3 having a positive refractive power, an N−1th lens unit, and an Nth lens unit, the lens units being arranged in order from an object side to an image side. The N−1th lens unit and the Nth lens unit are located on the image side with respect to an aperture stop SP.