A camera module includes: an optical imaging system including a frontmost lens disposed closest to an object side, a rearmost lens disposed closest to an imaging plane, and at least one middle lens disposed between the frontmost lens and the rearmost lens. An image-side surface of the rearmost lens is concave and an inflection point is formed on the image-side surface of the rearmost lens. 0.2 < D/TTL is satisfied, D being a shortest distance between the rearmost lens and the imaging plane, and TTL being a distance from an object-side surface of the frontmost lens to the imaging plane.

A lens apparatus includes zoom lens units configured to move in an optical axis direction for zooming, and a correction lens unit configured to move in the optical axis direction to correct change in a focal position due to change in an atmospheric pressure. The lens apparatus satisfies an inequality 0.4<|fair_t/fw|<6 where fair_t is a composite focal length of an air lens included in one of the zoom lens units having a smallest absolute value of the composite focal length among the zoom lens units and fw is a focal length of the lens apparatus at a wide-angle end.

A camera module includes: an optical imaging system including a frontmost lens disposed closest to an object side, a rearmost lens disposed closest to an imaging plane, and at least one middle lens disposed between the frontmost lens and the rearmost lens. An image-side surface of the rearmost lens is concave and an inflection point is formed on the image-side surface of the rearmost lens. 0.2<D/TTL is satisfied, D being a shortest distance between the rearmost lens and the imaging plane, and TTL being a distance from an object-side surface of the frontmost lens to the imaging plane.

A variable magnification optical system comprising a plurality of lens groups which includes a first negative lens group having negative refractive power, a second negative lens group disposed at a more image side than the first negative lens group and having negative refractive power, a third negative lens group disposed at a more image side than the second negative lens group and having negative refractive power; upon varying a magnification, distances between adjacent lens groups being varied; the first negative lens group being movable to include a component in a direction perpendicular to the optical axis as a vibration reduction lens group; the second negative lens group being moved along the optical axis upon carrying out focusing; and the predetermined conditional expression(s) being satisfied. The variable magnification optical system can attain a high optical performance and be made in small in size.

A variable magnification optical system comprising a plurality of lens groups which includes a first negative lens group having negative refractive power, a second negative lens group disposed at a more image side than the first negative lens group and having negative refractive power, a third negative lens group disposed at a more image side than the second negative lens group and having negative refractive power; upon varying a magnification, distances between adjacent lens groups being varied; the first negative lens group being movable to include a component in a direction perpendicular to the optical axis as a vibration reduction lens group; the second negative lens group being moved along the optical axis upon carrying out focusing; and the predetermined conditional expression(s) being satisfied. The variable magnification optical system can attain a high optical performance and be made in small in size.

A zoom lens includes, in order from an object side, a first lens group of which at least a part moves for focusing, a plurality of lens groups which move in zooming, an aperture stop, and a final lens group which does not move for zooming. The final lens group includes a separation element PR for separating an incident light thereon into a transmitted light and a reflected light, a relay unit LR having a positive refractive power on which the transmitted light is incident, and a relay unit LA having a positive refractive power on which the reflected light is incident. An inequality about Fwp/Fw is satisfied, where Fw is a focal length at a wide angle end of the zoom lens via the relay unit LR and FwP is a focal length at the wide angle end of the zoom lens via the relay unit LA.

A lens barrel which stably secures strength of a lens barrel without hampering miniaturization thereof. In an inner peripheral portion of a rotary cylinder rotatively driven while being inhibited from moving in a direction of an optical axis on an outer peripheral side of a straight advance cylinder which is movable in the direction of the optical axis while being inhibited from rotating on an outer peripheral side of a cam cylinder and has a through cam groove through which a first projecting portion of the cam cylinder passes, second projecting portions are provided on opposite sides of a straight advance groove of the rotary cylinder, with which the first projecting portion is to be engaged, in a circumferential direction. In an outer peripheral portion of the straight advance cylinder, circumferential grooves with which the second projecting portions are to be engaged are provided in the circumferential direction.

A projection lens includes a compound aspherical lens in which a resin layer is formed on a surface of a glass lens and a lens surface of the resin layer on the air contacting surface side has an aspherical shape. If the glass transition temperature of the resin layer is taken as Tg and its unit is taken as ° C., Tg of at least one of the resin layers is 150<Tg<280. The projection lens is configured to satisfy a given conditional expression with respect to the at least one of the resin layers.

A variable magnification optical system comprising a plurality of lens groups which includes a first negative lens group having negative refractive power, a second negative lens group disposed at a more image side than the first negative lens group and having negative refractive power, a third negative lens group disposed at a more image side than the second negative lens group and having negative refractive power; upon varying a magnification, distances between adjacent lens groups being varied; the first negative lens group being movable to include a component in a direction perpendicular to the optical axis as a vibration reduction lens group; the second negative lens group being moved along the optical axis upon carrying out focusing; and the predetermined conditional expression (s) being satisfied. The variable magnification optical system can attain a high optical performance and be made in small in size.

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.