A zoom lens system including, in order from an object side to an image side, a first lens unit having a positive refractive power that does not move for zooming, a second lens unit having a negative refractive power that moves during zooming, and a third lens unit having a positive refractive power that moves during zooming. In the zoom lens system, a distance between lens units that are adjacent to each other changes during zooming, the first lens unit includes a first a-lens unit that does not move for focusing, and a first b-lens unit that moves from the image side towards the object side during focusing from an infinite object to a near object, and the first a-lens unit comprises two positive lenses and two negative lenses.

A zoom lens includes, in order from a magnified side to a minified side, a first lens group, an aperture stop, and a second lens group. The second lens group has at least one aspheric surface. The zoom lens satisfies the conditions: 0.1<Ic/TTLw<0.15 and TTLw/EFLw≦10, where Ic denotes a radius of an image circle, TTLw denotes a total track length of the zoom lens in the wide configuration, and EFLw denotes an effective focal length of the zoom lens in the wide configuration.

A zoom lens includes in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, and a fourth lens unit having a negative refractive power, and includes an aperture stop which is disposed between the second lens unit and the fourth lens unit, and the first lens unit includes a negative lens and a plurality of positive lenses, and at the time of zooming from a wide angle end to a telephoto end, a distance between the first lens unit and the second lens unit widens, a distance between the second lens unit and the third lens unit narrows, and a distance between the third lens unit and the fourth lens unit changes, and the zoom lens satisfies predetermined conditional expressions.

Comprising a first lens group G1 having positive refractive power, disposed at the most object side, and an image side lens group disposed at a side closer to an image than the first lens group G1, upon zooming, at least a distance between the first lens group G1 and the image side lens group being varied, the image side lens group comprising a vibration reduction lens group GVR which is moved so as to have a component in a direction perpendicular to the optical axis and a focusing lens group GF which is moved along the optical axis upon focusing, thereby providing a variable magnification optical system which has a higher optical performance, an optical apparatus and a method for manufacturing a variable magnification optical system.

An observation optical system unit includes a first lens which is positioned closest to an object side, among rear-group lenses, and which is configured by a stepped lens including a proximal portion, an outer circumference of which is held by a rear-group lens frame, and a protruding portion formed to have an outer circumference smaller than the outer circumference of the proximal portion and protruding into a region where a moving lens frame is allowed to advance and retract, where the moving lens frame overlaps with the protruding portion at a retracted position.

A camera lens module in which an optical system is configured to include five sheets of lenses is provided. In the camera lens module, first, second, third, fourth and fifth lenses are sequentially arranged from an object side, and the first lens performs a zooming operation while moving along an optical axis. Accordingly, the optical system is configured to include five sheets of lenses for performance of a zooming operation and to allow only the first lens to perform the zooming operation, so that it is possible to manufacture a high-resolution optical system in a compact size and to perform the zooming operation at a high speed.

Digital cameras, optical lens modules for such digital cameras and methods for assembling lens elements in such lens modules. In various embodiments, the digital cameras comprise an optical lens module including N≥3 lens elements L.sub.i, each lens element comprising a respective front surface S.sub.2i−1 and a respective rear surface S.sub.2i. In various embodiments the first lens element toward the object side, L.sub.1 and its respective front surfaces S.sub.1 have optical and/or mechanical properties, such as a clear aperture, a clear height and a mechanical height that are larger than respective properties of following lens elements and surfaces. This is done to achieve a camera with large aperture stop, given a lens and/or camera height.

Some embodiments include a fixed chassis structure and a moveable carriage body carrying one or more lenses. The fixed chassis structure includes a magnetic friction track. The moveable carriage body carries one or more lenses. An electrically-controllable magnet is mounted to the moveable carriage body for generating a magnetic attraction force between the magnet and the magnetic friction track. The moveable carriage body is movably mounted to the chassis to allow movement along an optical axis through the one or more lenses. An inertial actuator is mounted to the moveable carriage body in an alignment such that the axis of motion of the actuator is parallel to the optical axis through the one or more lenses. The moveable carriage body is held in place with respect to the at least one allowed degree of freedom by one or more friction forces resulting from the magnetic attraction force.

A zoom lens comprising in order from an object side, a first lens unit having a negative refractive power, a second lens unit having a negative refractive power, a lens unit having a positive refractive power, and a rearmost lens unit having a negative refractive power, and the rearmost lens unit is positioned nearest to an image in the plurality of lens units, and at the time of zooming, distances between the lens units in the plurality of lens units change. Moreover, an image pickup apparatus includes the zoom lens, and an image pickup element having an image pickup surface.

Provided is a small zoom lens having a high zoom ratio and easily designed to achieve favorable optical properties in an entire zooming range. A zoom lens includes, in order from object side to image side, a positive first unit, a negative second unit, an aperture stop, and a rear group including multiple units. Intervals between the adjacent units are changed during zooming. In the rear group, a positive lens unit is arranged on the most image side, and a negative lens unit is on the object side of the positive lens unit. The aperture stop not moving for zooming, but the second unit and the negative lens unit moving during zooming. Focal lengths of the second unit and the positive and negative lens units, and movement amounts of the second and negative lens units, respectively, during zooming from wide angle end to telephoto end are appropriately set.