The disclosure provides a zoom lens assembly, which sequentially includes from an object side to an image side along an optical axis: a first lens group; a second lens group with a positive refractive power, spaced from the first lens group by a first air space and movable on the optical axis; a third lens group with a positive refractive power, spaced from the second lens group by a second air space and movable on the optical axis; and a fourth lens group, spaced from the third lens group by a third air space; wherein a Total Track Length (TTL) of the zoom lens assembly and a difference Δf between an effective focal length of the zoom lens assembly at a wide end and an effective focal length of the zoom lens assembly at a tele end satisfy 2.5<TTL/|Δf|<4.0.

An image capture apparatus and a zoom lens are provided. The zoom lens in accordance with an exemplary embodiment of the invention includes a mount, a guide unit, a plurality of lens groups and a driving device. The guide unit is disposed in the mount in a first direction. The lens groups are disposed in the mount and include at least one movable lens group which can be moved along the guide unit. The driving device is configured for driving the movable lens group. The driving device includes magnets and coils. The magnets are fixed to one of the movable lens group and the mount, while the coils are fixed to the other of the movable lens group and the mount. The magnets and/or the coils are arranged in the first direction.

The zoom lens consists of, in order from an object side: a first lens group that has a positive refractive power; a middle group that includes a plurality of lens groups each moving by changing a spacing with an adjacent lens group during zooming; and a final lens group that remains stationary during zooming and has a positive refractive power. Among the plurality of lens groups that move during zooming in the middle group, an image side movable lens group, which is a lens group disposed closest to the image side, has a negative refractive power.

A zoom lens forms an intermediate image at a position conjugate to a reduction side imaging plane and forms the intermediate image again on a magnification side imaging plane. The zoom lens includes a plurality of lens groups including at least two movable lens groups, which move by changing spacings between the groups adjacent to each other in a direction of an optical axis during zooming, at a position closer to the reduction side than the intermediate image. Among the plurality of lens groups, a final lens group closest to the reduction side has a positive refractive power, and remains stationary with respect to the reduction side imaging plane during zooming. The zoom lens satisfies predetermined conditional expressions (1) and (2) about the focal lengths of the movable lens groups.

A method is provided for adjusting a loupe including an eyepiece and a tube framework having a first optical system adjacent to an object and a second optical system adjacent to the eyepiece. At least two zoom lenses in the first optical system shift along an optical axis between a first and a second position to change magnification. The method includes shifting at least one lens in the first optical system such that a distance at which the object is focused when the zoom lenses are shifted to the first position is substantially equal to a distance at which the object is focused when the zoom lenses are shifted to the second position; and then shifting at least one lens in the second optical system along the optical axis such that the object is focused when the zoom lenses are shifted to the first position or the second position.

A zoom lens forms an intermediate image at a position conjugate to a reduction side imaging plane and forms the intermediate image again on a magnification side imaging plane. The zoom lens includes a plurality of lens groups including at least two movable lens groups, which move by changing spacings between the groups adjacent to each other in a direction of an optical axis during zooming, at a position closer to the reduction side than the intermediate image. Among the plurality of lens groups, a final lens group closest to the reduction side has a positive refractive power, and remains stationary with respect to the reduction side imaging plane during zooming. The zoom lens satisfies predetermined conditional expressions (1) and (2) about the focal lengths of the movable lens groups.

The disclosure provides a zoom lens assembly, which sequentially includes from an object side to an image side along an optical axis: a first lens group; a second lens group with a positive refractive power, spaced from the first lens group by a first air space and movable on the optical axis; a third lens group with a positive refractive power, spaced from the second lens group by a second air space and movable on the optical axis; and a fourth lens group, spaced from the third lens group by a third air space; wherein a Total Track Length (TTL) of the zoom lens assembly and a difference Δf between an effective focal length of the zoom lens assembly at a wide end and an effective focal length of the zoom lens assembly at a tele end satisfy 2.5<TTL/|Δf|<4.0.

Disclosed herein is an optical imaging lens group, including, in order from an object side to an image side along an optical axis: a first lens group having a refractive power, in which an image side surface of a lens closest to an imaging side is concave; a second and a third lens group having a refractive power; and a fourth lens group having a negative refractive power, in which an image side surface of a lens closest to the imaging side is concave and includes at least one inflection point, wherein the first lens group is a fixed group, and the second, third and fourth lens groups move on the optical axis to realize continuous zoom from a wide-angle end to a telephoto end; and an on-axis distance TTL and an effective focal length ft of the optical imaging lens group at the telephoto end satisfy: 0.8<TTL/ft<1.5.

There is provided an optical imaging system including a prism, a first fixed lens group, a first movable lens group, a second movable lens group, and a second fixed lens group. The prism is configured to refract light reflected from an object side toward an imaging plane and a reflecting member. The prism is disposed on the first fixed lens group and the first movable lens group is configured to change a position of the imaging plane so that an overall focal length is changed. The second movable lens group is configured to adjust a position of the imaging plane so that a focal length for an object is adjusted. The imaging plane is disposed on the second fixed lens group.

There is provided an optical imaging system including a prism, a first fixed lens group, a first movable lens group, a second movable lens group, and a second fixed lens group. The prism is configured to refract light reflected from an object side toward an imaging plane and a reflecting member. The prism is disposed on the first fixed lens group and the first movable lens group is configured to change a position of the imaging plane so that an overall focal length is changed. The second movable lens group is configured to adjust a position of the imaging plane so that a focal length for an object is adjusted. The imaging plane is disposed on the second fixed lens group.