An image capturing lens system includes three lens groups including five lens elements. The three lens groups are, in order from an object side to an image side: first, second and third lens groups. The five lens elements are, in order from the object side to the image side: first, second, third, fourth and fifth lens elements. The first lens element has an object-side surface being convex in a paraxial region thereof. The second lens element has negative refractive power. At least one lens element has an inflection point. A focal length of the image capturing lens system is varied by changing axial distances between the three lens groups in a zooming process. The image capturing lens system has a long-focal-length end and a short-focal-length end. The second lens group is moved relative to the first lens group along an optical axis in the zooming process.

An embodiment provides an imaging lens comprising first to third lens groups arranged sequentially from an object side to an image side and having refractive power, wherein the distances of the second lens group and the third lens group from the first lens group are variable such that a tele mode having a narrow angle of view and a wide mode having a wide angle of view can be implemented, the EFL in the tele mode is no more than 2.5 times the EFL in the wide mode, 2<F.sub.number<5 and 15 mm<TTL≤40 mm.

A zoom objective comprises housing lens, a first movable lens, and a first gearless motor. The first gearless motor is adapted to cause a first longitudinal movement of the first movable lens relative to the housing lens. A method of operating a zoom objective provides a first movable lens, a housing lens, and a first gearless motor. The method includes moving the first movable lens relative to the housing lens by a force generated by the first gearless motor.

An imaging device includes a lens and a circuit configured to control the lens to move in a first direction along an optical axis of the lens, control capture of a plurality of first images via the lens when the lens is positioned at a plurality of first positions, respectively, control the lens to move in a second direction opposite to the first direction, control capture of one or more second images via the lens when the lens is positioned at one or more second positions, respectively, and determine a focus position based on one or more of a plurality of first evaluation values calculated from the plurality of first images and one or more second evaluation values calculated from the one or more second images. Each of the plurality of first evaluation values and the one or more second evaluation values indicates a corresponding focus state.

An imaging lens consists of, in order from the object side, a first lens group, a stop, a positive second lens group, and a third lens group. During focusing, at least the second lens group moves and the third lens group does not move. The second lens group includes at least two negative lenses. The third lens group consists of one negative lens and one positive lens.

A lens unit that fixes and holds a lens after the lens is moved and adjusted in parallel with a receiving surface to position the lens in an optical axis direction includes a lens holder configured to hold the lens and including the receiving surface, a pressing member configured to be fixed to the lens holder, and an elastic member configured to press the lens against the lens holder and located between the pressing member and the lens, wherein the lens holder includes an opening through which a tool for moving and adjusting the lens in parallel with the receiving surface by pressing an outer peripheral surface of the lens is inserted, and wherein a position of the lens is fixed by the pressing member and the elastic member.

A lens barrel includes one or more movable lens groups, and a cam barrel associated with the one or more movable lens groups and configured to balance a center of gravity of the one or more movable lens groups.

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 camera module includes a base, a plurality of guide bars coupled to the base, a first mover disposed in the base, the first mover including at least one lens disposed therein, and a second mover disposed in the base, the second mover including at least one lens disposed therein, wherein each of the first mover and the second mover includes a plurality of guide grooves formed therein to allow the guide bars to be disposed therein, and wherein each of the plurality of guide grooves includes a protruding portion formed to be in contact with a respective one of the guide bars.

A method to design projection lenses or zoom lenses with distorted or uncorrected pupil aberration (mostly Spherical Aberration or spherochromatism). By introducing some pupil aberration, the designer has a new variable to correct for field and aperture aberrations. The result is a design that requires fewer lens count for the same performance parameters than more complex projection lenses, and is more compact. Lenses designed by the method are illustrated.