A zoom optical system comprises, in order from an object side: a first lens group having positive refractive power; a front-side lens group; an intermediate lens group having positive refractive power; and a rear-side lens group. The front-side lens group is composed of one or more lens groups and has a negative lens group. At least part of the intermediate lens group is a focusing lens group. The rear-side lens group is composed of one or more lens groups. Upon zooming, distances between the first lens group and the front-side lens group, between the front-side lens group and the intermediate lens group, and between the intermediate lens group and the rear-side lens group change. The following conditional expressions are satisfied:
−10.000<fF/fRF<10.000
0.010<|fF/fXR|<10.000
where fF denotes a focal length of the focusing lens group, fRF denotes a focal length of a lens group closest to the object side in the rear-side lens group, and fXR denotes a focal length of a lens group closet to an image surface in the front-side lens group.

A zoom lens consists of, in order from an object side, a positive first lens group, a negative moving lens group, a first positive moving lens group, a second positive moving lens group, and a subsequent lens group including a stop. During zooming, the first lens group is not moved, and the negative moving lens group, the first positive moving lens group, and the second positive moving lens group are moved. The first positive moving lens group consists of a positive single lens and a cemented lens obtained by cementing a positive lens and a negative lens. The zoom lens satisfies a predetermined conditional expression.

The zoom lens includes, in order from an object side to an image side, a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, a middle group including two or more lens units, and a rear group including one or more lens units and having a positive refractive power. The first lens unit does not move for zooming. During zooming, the second lens unit moves and a distance between each adjacent lens units changes. In all lens units of the zoom lens, during zooming the second lens unit moves by a largest moving amount and has a largest zooming ratio between a wide-angle end and a telephoto end. Predetermined conditions are satisfied.

The zoom lens consists of a first unit, a second unit, a third unit, a fourth unit, and a fifth unit in order from the magnification side, and forms an intermediate image. The first unit consists of one lens group which has a positive refractive power. The second unit consists of two lens groups which move during magnification change and has a negative refractive power as a whole at the wide angle end. The third unit includes one or more lens groups which move during magnification change. The fourth unit includes one or more lens groups which move during magnification change.

A zoom optical system comprises, in order from an object side: a first lens group having positive refractive power; a front-side lens group; an intermediate lens group having positive refractive power; and a rear-side lens group. The front-side lens group is composed of one or more lens groups and has a negative lens group. At least part of the intermediate lens group is a focusing lens group. The rear-side lens group is composed of one or more lens groups. Upon zooming, distances between the first lens group and the front-side lens group, between the front-side lens group and the intermediate lens group, and between the intermediate lens group and the rear-side lens group change. At least one of the following conditional expressions is satisfied:
0.010<fF/fXR<10.000
2.250<TLW/ZD1<10.000
where fF denotes a focal length of the focusing lens group, fXR denotes a focal length of a lens group closet to the image surface in the front-side lens group, TLW denotes an entire length of the optical system in a wide angle end state, and ZD1 denotes a movement amount of the first lens group upon zooming from the wide angle end state to a telephoto end state.

A zoom lens includes, 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, one or two intermediate lens units having positive refractive powers, and a final lens unit having a positive power. A distance between each pair of adjacent lens units changes in zooming from a wide-angle end to a telephoto end. The one or two intermediate lens units include three or four lenses. The one or two intermediate lens units include a single lens having a positive refractive power and being closest to the image side. The final lens unit includes three or four lenses. The zoom lens satisfies specified conditional expressions.

Provided is an optical device including an optics including at least two moving groups that are movable along an optical axis and share portions of driving regions; a plurality of actuators configured to move the at least two moving groups along the optical axis, respectively; and a control unit configured to control the positions of the at least two moving groups by operating the actuators, wherein the control unit moves the at least two moving groups independently, such that the position coordinates of the at least two moving groups in one integrated coordinates system do not coincide with each other.

A zoom lens includes, in order from an object side to an image side, a first lens unit having a positive refractive power, a plurality of lens units which move in zooming, and a final lens unit having a positive refractive power, an interval between each pair of adjacent lens units changing in zooming, the plurality of lens units including a lens unit having a negative refractive power, the first lens unit including a negative lens and a positive lens, at least a part of the first lens unit moving for focusing, the first lens unit including a negative lens made of a material satisfying inequalities defined by a refractive index, an Abbe number, and a partial dispersion ratio, and the zoom lens satifying an inequality defined by a maximum value of an Abbe number of at least one positive lens of the first lens unit.

Provided is a zoom lens including in order from an object side: a positive first lens unit not moving for a change in magnification; a negative second lens unit moving for a change in magnification; and two or three rear lens units having a positive refractive power as a whole, at least one of the rear lens units being configured to move for a change in magnification. The first lens unit includes a negative first lens sub-unit not moving for focusing, a positive second lens sub-unit moving for focusing, a third lens sub-unit not moving for focusing, and a positive fourth lens sub-unit moving for focusing. An amount of movement of the second lens sub-unit during focusing from infinity to a minimum object distance, and an amount of movement of the fourth lens sub-unit during focusing from infinity to the minimum object distance satisfy a specific conditional expression.

A zoom lens includes, in order from an object side to an image side, first, second and third lens units having positive, negative and positive refractive powers. The first lens unit moves during zooming. During zooming from a wide-angle end to a telephoto end, a distance between the first and second lens units widens, and a distance between the second and third lens units narrows. The first lens unit consists of three or less lenses. The second lens unit consists of, in order from the object side to the image side, a first single lens as a spherical lens having a negative refractive power, a cemented lens in which a lens having a negative refractive power and a lens having a positive refractive power are cemented, and a second single lens as a spherical lens having a negative refractive power. A predetermined condition is satisfied.