A control apparatus includes an acquirer (129a) that acquires a first signal and a second signal that correspond to output signals of a first photoelectric converter and a second photoelectric converter, respectively, the first and second photoelectric converters receiving light beams passing through different pupil regions of an image capturing optical system from each other, and a calculator (129b) that calculates a correlation value of the first signal and the second signal to calculate a defocus amount based on the correlation value, and the calculator corrects the correlation value based on a light receiving amount of at least one of the first photoelectric converter and the second photoelectric converter.

On embodiment of the invention discloses an optical lens including five lens group and an aperture stop. Each lens group includes at least one lens with refractive power, and the aperture stop is fixed in a position between a second lens group and a third lens group. Further, a distance between a first lens group and a fifth lens group remains fixed during zooming or focusing, and respective distances of the second lens group and a fourth lens group relative to the fifth lens group vary during zooming or focusing.

The anamorphic objective zoom lens includes, along an optical axis and in order from an object space to an image space: at least a negative (−) power spherical first lens group; an anamorphic second lens group, spherical third lens group preferably having positive (+) power, a variable power spherical fourth lens group and a positive (+) power spherical fifth lens group. The aperture stop is located before, after or preferably within the spherical fifth lens group. All spherical lens groups contain spherical and piano refractive optical surfaces. The anamorphic second lens group contains cylindrical and plano optical surfaces with at least one cylindrical surface oriented at substantially 90 degrees about at least one other cylindrical surface. The spherical first lens group may provide focusing. The variable power spherical fourth lens group provides zooming. The spherical third and fifth lens groups may provide compensation for thermal defocus.

An optical system includes a plurality of lenses. The distance from the object side lens surface of a lens arranged an the most object side to the image plane is longer than the focal length of the entire system. The material of a positive lens G1p arranged on the most object side among positive lenses included in the optical system, and the arrangement and material of a negative lens Gn located on the most object side among negative lenses arranged an the image side of the positive lens G1p are appropriately set.

In an optical system which includes a positive lens Gp and in which a distance on an optical axis from an object-side lens surface of a lens disposed closest to an object side to an image surface is shorter than a focal length of an entire system, an arrangement and a material of the positive lens Gp, and an arrangement of a focus unit are set appropriately.

A zoom lens system according to the present disclosure includes a plurality of lens groups each of which is made up of at least one lens element. The zoom lens system includes, in order from an object side to an image side: a first focusing lens group having a negative power; and a second focusing lens group having a positive power, wherein when zooming is performed from a wide end to a telephoto end, the first focusing lens group and the second focusing lens group move along an optical axis, when focusing is performed from an infinity focusing state to a proximity object focusing state, the first focusing lens group and the second focusing lens group move to perform the focusing, and a predetermined condition is satisfied.

A projection zoom lens assembly for a digital cinema projection system includes three optical groups. A first optical group includes one or more wide angle lenses for projecting digital cinema images. A second optical group includes a set of zoom optical groups each comprising two or more lenses, including a first independently movable zoom group, a second independently movable zoom group, and a third zoom group. A third optical group includes multiple lenses for receiving images for projection.

A zoom lens, a camera module, and a mobile terminal. The zoom lens includes a first lens group, a second lens group, and a third lens group arranged along an axis extending from an object side to an image side, where the first lens group is a fixed lens group with positive focal power nearest an object side, where the second lens group is a zoom lens group with negative focal power, where the third lens group is a compensative lens group with positive focal power nearest an image side to an image side, and where the second lens group is configured to move, in a zooming process of the zoom lens from a short-focal end to a long-focal end, toward the image side along an optical axis, and the where third lens group is configured to move toward the object side along the optical axis.

A variable magnification optical system according to the present invention includes a C lens group having positive refractive power, a B lens group having negative refractive power, and an A lens group having positive refractive power in order from an image side and includes an N lens group having negative refractive power on an object side in relation to the A lens group, wherein when zooming from a wide angle end to a telephoto end, at least the A lens group, the B lens group, and the N lens group are moved relative to an image plane and a predetermined conditional expression is satisfied.

A variable magnification optical system according to the present invention includes a C lens group having positive refractive power, a B lens group having negative refractive power, and an A lens group having positive refractive power in order from an image side and includes an N lens group having negative refractive power on an object side in relation to the A lens group, wherein when zooming from a wide angle end to a telephoto end, at least the A lens group, the B lens group, and the N lens group are moved relative to an image plane and a predetermined conditional expression is satisfied.