A zoom lens comprising a plurality of lens units. The plurality of lens units consists of, in order from an object side to an image side, a first lens unit having negative refractive power, a second lens unit having positive refractive power, a third lens unit having negative refractive power, and a fourth lens unit having positive refractive power. A distance between adjacent lens units changes during zooming from a wide-angle end to a telephoto end. The first lens unit includes three or more lenses. The first lens unit is fixed relative to an image plane during zooming. A predetermined inequality is satisfied.

An inner focus lens system includes, in order from an object side to an image side, a first lens unit, an aperture stop, a second lens unit having a positive refractive power, a third lens unit having a negative refractive power, and a fourth lens unit having a positive refractive power. The first lens unit has negative lens(es) and positive lens(es), the second lens unit has negative lens(es) and positive lens(es), the third lens unit has negative lens(es), the fourth lens unit has positive lens(es), at the time of focusing on an object at a short distance from an object at infinity, the third lens unit moves to an image side to lengthen a distance to the second lens unit and to shorten a distance to the fourth lens unit, and the following conditional expression is satisfied: 6<f3/f<1.

A zoom lens includes, in order from object side, a negative first unit, a positive second unit, a negative third unit, and a positive fourth unit, wherein, for zooming to telephoto end, the second unit moves toward object side, the third unit moves and an interval between each pair of adjacent units is changed, wherein, at telephoto end as compared to wide angle end, the interval between the first and second units is smaller, the interval between the second and third units is larger, the interval between the third and fourth units is larger, and the fourth unit is positioned closer to image side, wherein the third unit consists of a single optical element, wherein the fourth unit includes plural lenses arranged at intervals, and wherein focal lengths of the third and fourth units and the interval between the third and fourth units at telephoto end are appropriately set.

An optical zoom including a movable pupil that moves according to a movement law, comprises four successive groups of lenses, the first group and the fourth group being fixed, the second group and the third group being movable and placed between the first and fourth groups, the second group being a convergent group and the third group being a divergent group. In a first variant, the diameter of the movable pupil varies according to a variation law, depending on the movement law of the movable pupil. In a second variant, the optical zoom includes a movable stop, the movable stop moving according to a second movement law, the diameter of this stop varying according to a second variation law, depending on the second movement law of the movable stop.

A zooming optical system includes a first lens group having negative refractive power, a second lens group having positive refractive power, a third lens group having negative refractive power, and a fourth lens group having positive refractive power, in that order from an object side. The first lens group has at least one cemented lens having positive refractive power. Each of the first lens group, the second lens group, the third lens group, and the fourth lens group are configured to move along a direction of an optical axis in zooming. Conditional expression (1) below is satisfied:
10.0<f2/f1<2.0(1), where f1 is a focal length of the first lens group, and f2 is a focal length of the second lens group.

A zoom lens with a bent optical path includes, in order from the object side to the image side, a first lens unit including the reflecting member and having a negative refractive power, a second lens unit having a positive refractive power, a third lens unit having a negative refractive power, and a fourth lens unit having a positive refractive power. During zooming from the wide angle end to the telephoto end, the second lens unit moves closer to the first lens unit only toward the object side, the third lens unit moves in such a way that it becomes closest to the second lens unit at an intermediate focal length position in the course of zooming as compared to the state at the wide angle end and the state at the telephoto end, and the fourth lens unit moves. The zoom lens satisfies a certain condition.

The zoom lens according to the present invention includes, in order from an object side to an image side, a first lens unit with a negative refractive power and a rear lens group including one or more lens units, in which intervals between adjacent ones of the lens units are changed during zooming and focusing. The first lens unit includes three or more negative lenses. The rear lens group includes a focus lens unit with a negative refractive power that moves during focusing. A focal length of the first lens unit, a shortest focal length of the zoom lens, curvature radii of object-side and image-side lens surfaces of a lens in the first lens unit disposed closest to the object side, and a focal length of the focus lens unit are appropriately set.

A zoom lens comprises, in order from an object, a first lens group (G1) having negative refractive power, a second lens group (G2) having positive refractive power, a third lens group (G3) having negative refractive power, and a fourth lens group (G4) having positive refractive power to satisfy the following conditional expression:

1.60<(f1)/fw<2.50 where, f1 denotes a focal length of the first lens group; and fw denotes a focal length of the zoom lens as a whole in a wide-angle end state.

The zoom lens consists of, in order from the object side, a first lens group that has a negative refractive power; a second lens group that has a positive refractive power; a third lens group that has a negative refractive power; and a fourth lens group that has a positive refractive power. During zooming, in each lens group, distances between the adjacent groups in the direction of the optical axis are changed. The first lens group consists of, in order from the object side, a first lens having a negative refractive power, a second lens having a negative refractive power, and a third lens having a positive refractive power. The third lens group consists of a negative lens. During focusing, only the third lens group moves along the optical axis. The zoom lens satisfies predetermined conditional expressions.

A zoom lens includes in order from an object side, a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, a third lens unit having a negative refractive power, and a fourth lens unit having a positive refractive power. At the time of zooming, distances between lenses vary. A distance between the first lens unit and the second lens unit becomes smaller at a telephoto end than at a wide angle end, and a distance between the second lens unit and the third lens unit becomes longer at the telephoto end than at the wide angle end, and the following conditional expressions (1), (2), and (3) are satisfied:

0.4<|f1|/|f2|<1.2(1)

0.3<L2/L1<0.95(2)

0.6<Lt/Lw<1(3).