A zoom lens includes, in order from an object side along an optical axis, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, and a third lens group G3 having positive refractive power. Upon zooming from a wide-angle end state W to a telephoto end state T, a distance between the first lens group G1 and the second lens group G2 increases, and a distance between the second lens group G2 and the third lens group G3 decreases. Given conditions are satisfied. Accordingly, a zoom lens having high optical performance with suppressing variations in aberrations, an optical apparatus equipped therewith, and a method for manufacturing the zoom lens are provided.

A variable magnification optical system consists of, in order from an object side to an image side, a first lens group, a second lens group, and a subsequent lens group. The variable magnification optical system satisfies a predetermined conditional expression for a partial dispersion ratio related to F line, C line, and a wavelength of 1970.09 nm, a d-line back focus of the variable magnification optical system at a telephoto end, a back focus in any one wavelength from a wavelength of 1300 nm to a wavelength of 2325.42 nm at the telephoto end, and a d-line focal length of the variable magnification optical system at the telephoto end.

A variable magnification optical system includes, in order from an object side, a first lens group having positive refractive power; a second lens group having negative refractive power; and a third lens group having positive refractive power; upon zooming from a wide-angle end state to a telephoto end state, a distance between the first lens group and the second lens group and a distance between the second lens group and the third lens group being varied. The variable magnification optical system further includes a V lens group GV having negative refractive power and being moved to have a component in a direction perpendicular to the optical axis, and an F lens group GF having positive refractive power and being moved along the optical axis upon focusing from an infinitely distant object to a close object, the V lens group GV being disposed on the more object side than the F lens group GF. Thereby, it is possible to provide the compact variable magnification optical system with a high zoom ratio and high performance, an optical apparatus therewith and a method for manufacturing the variable magnification optical system.

An optical system includes, in order from an object side, a first lens unit having positive refractive power, a second lens unit having negative refractive power, and a third lens unit having positive refractive power. A distance between adjacent lens units changes during focusing. During focusing from an infinity object to the closest object, the first and third lens units do not move and the second lens unit moves toward the image side. The third lens unit consists of, in order from the object side, a first subunit having positive refractive power, a second subunit having negative refractive power, and a third subunit having positive refractive power. The second subunit moves in a direction including a component in a direction orthogonal to an optical axis during image stabilization. The second subunit includes positive and negative lenses. A predetermined condition is satisfied.

A lens optical system includes a first lens group in which a first lens of an object side is composed of a meniscus lens having a positive refractive power, and having a positive refractive power as a whole, a second lens group arranged closer to an image side I than the first lens group, the second lens group being a focusing group for correcting a change in image distance depending on a change in object distance, being composed of a single lens, and having a negative refractive power as a whole, and a third lens group arranged closer to the image side I than the second lens group, the third lens group including a plurality of lenses and having a positive refractive power as a whole.

The lens apparatus includes an optical system, a voltage transformation unit, and an actuator. A first lens unit of the optical system is moved toward the object side during zooming from a wide-angle end to a telephoto end. The voltage transformation unit includes coils. The actuator is configured to be driven by a voltage output from the voltage transformation unit and to move a part of the lens units in the optical system during focusing. The coil is disposed at a position that is separated from a position of a most object-side surface of the optical system at the wide-angle end, toward the image side by a maximum or more moving amount of the first lens unit, and is closer to the object side than a most image-side surface of the optical system at the wide-angle end.

A variable magnification optical system consists of, in order from an object side to an image side, a first lens group, a second lens group, and a subsequent lens group. The variable magnification optical system satisfies a predetermined conditional expression for a partial dispersion ratio related to F line, C line, and a wavelength of 1970.09 nm, a d-line back focus of the variable magnification optical system at a telephoto end, a back focus in any one wavelength from a wavelength of 1300 nm to a wavelength of 2325.42 nm at the telephoto end, and a d-line focal length of the variable magnification optical system at the telephoto end.

A lens apparatus includes two optical systems. Each of the two optical systems includes, in order from an object side to an image side, a first lens unit having positive refractive power, a second lens unit having negative refractive power, a first reflective surface, a second reflective surface, and a rear lens unit having positive refractive power. At least a distance between the first lens unit and the second lens unit and a distance between the second lens unit and the first reflective surface are changed during magnification variation. A predetermined condition is satisfied.

A head-mountable display device for displaying an image received from a microscope comprises a first display configured to display a first image of a part of an object, the first image received from a microscope. Further, the head-mountable display device comprises a first optical arrangement located in front of the first display. The first optical arrangement comprises at least one lens. Additionally, the head-mountable display device comprises a mounting structure configured to fasten the first display to the head of a user. The head-mountable display device is configured to allow a direct line of sight from a first eye of the user to the object in a field of view of the user outside of the first display while the user is watching the first display through the first optical arrangement, if the mounting structure is fastened to the head of a user. An angle between a display direction and the direct line of sight is less than 50° and the display direction is orthogonal to the first display.

An optical system (LS) Includes lenses (L22,L23) satisfying the following conditional expressions,
νdLZ<35.0, and
0.702<θgFLZ+(0.00316×νdLZ),
where νdLZ: Abbe number of the lens with reference to d-line, and θgFLZ: a partial dispersion ratio of the lens, wherein θgFLZ is defined by the following expression,
θgFLZ−(ngLZ−nFLZ)/(nFLZ−nCLZ). wherein a refractive index of the lens with reference to g-line is ngLZ, a refractive index of the lens with reference to F-line is nFLZ, and a refractive index of the lens with reference to C-line is nCLZ.