Abstract: A lens is provided with a first and second lens groups which can focus not only with their concurrent movement along the optical axis but also with the movement of either one of the two lens groups. The first and second lens groups are respectively carried by first and second movable barrels. First means is provided for shifting both of first and second movable barrels concurrently in accordance with manual focus control. Second means is provided for shifting the second movable barrel without causing any movement of the first movable barrel. Thus, members to be moved for focusing upon automatic focus control are less in number in comparison with the members upon manual focus control.

Abstract: A zoom lens barrel has incorporated therein two lens groups, the first of which is moved by a single operating ring for focusing and also for zooming. A cam member and an intermediate member are supported on a stationary cylinder. The first lens group is axially moved for focusing by the rotation of the operating ring. By way of the intermediate member, the stationary cylinder and the cam member, the operating ring, when axially moved, axially moves the first and second lens groups at the same time by different amounts for zooming. The barrel affords a high zooming ratio with ease, while the optical system can be designed compactly in a small size.

Abstract: A zoom lens barrel is constructed such that the axial movement and rotation of a single operation ring relative to a stationary barrel causes zooming and focusing respectively and provides a device for providing constant magnification photography. This is accomplished by a plurality of cam grooves provided on one of the operation ring and the stationary barrel and a guide pin provided on the other of the operation ring and the stationary barrel and releasably engageable with each of the cam grooves. Each of the cam grooves forces the operation ring to rotate upon axial movement of the operation ring through the engagement with the guide pin such that magnification remains constant during focusing. The magnification that remains constant during focusing varies depending on which of the cam grooves the guide pin is engaged with.

Abstract: In a shifting device, wherein a shifting operation is effected by the engagement of a guide pin with a cam groove, which is delineated by a control face for guiding the guide pin, and a back-up face serving no guide pin guidance function. The guide pin is so constructed as to be normally maintained in engagement with the control face of the cam groove, so as to be shifted by engagement with the control face of the cam groove during the normal shifting operation. In the event that an undesired shock is imparted to the shifting device, the guide pin is adapted to impinge on the back-up face of the cam groove, rather than on the control face thereof, so that the engagement between the guide pin and the control face of the cam groove is maintained in an optimum condition, without being damaged due to such a shock, thus ensuring an accurate shifting operation of the shifting device.

Abstract: A diaphragm control mechanism for a camera objective wherein the diaphragm aperture is maintained fully open before camera operation in order to facilitate framing and focusing of the objective system and is then stopped down in response to a camera release operation to a value manually preset or automatically determined. The fully open diaphragm aperture is adjusted in accordance with movement of a component or components of the objective for the sake of adjustment of the objective, for example, to change its focal length.

Abstract: A zoom lens barrel capable of indicating adjusted distance and focal length is of compact construction having only those members essential for focusing and zooming. No special scale member is provided, although a focal length or zoom ratio scale extends circumferentially along the outer periphery of a cam ring which is rotated upon the zooming operation, while a distance scale extends circumferentially along an operating ring substantially at its rearward end. A stationary barrel on and in which the cam ring and the operating ring, respectively, are fitted has a window for the focal length or zoom ratio scale and an index at an external position adjacent the rearward end of the operating ring. Rotation of the ring causes helicoid threads to axially move a first lens group for focusing and the adjusted distance on the distance scale is indicated by the index. Axial movement of the operating ring axially moves the front lens group as well.

Abstract: A zoom lens barrel has first and second manually operable members movable for effecting a zooming operation in different directions. The first operable member is axially movable for effecting movement of a first lens group and is threaded with an axially movable follower member such that the first operable member and the follower member are axially moved in response to axial movement of the other. A first pin-slot arrangement interconnects the follower member and a rotatable intermediate cam ring with one another such that the cam ring is rotated in response to axial movement of the follower member while the follower member is axially moved in response to rotation of the cam ring. A second pin-slot arrangement interconnects the cam ring with a lens frame supporting a second lens group such that the second lens group is moved for zooming in response to rotation of the cam ring with a given spatial relationship with respect to the first lens group.

Abstract: An impact resistant zoom lens with a common focusing and zooming ring includes a camera mountable main barrel, front and rear axially movable lens carrying mounts, a control ring rotatably and slidably engaging the barrel and affixed to the front mount, an axial sleeve helicoid coupled to the first mount, a cylindrical cam rotatably supported by the barrel and longitudinally stationary therein and followers carried by the axial sleeve rearwardly thereof and by the rear mount and slidably engaging respective cam slots in the cam and guide tracks in the barrel. In order to prevent damage to the lens mechanism attendant to an impact on the front mount abutment members or faces are located on the front mount or sleeve and have large areas in stop engagement when the front mount is in its rearmost position with the follower movable therewith being shortly spaced from the rear end of the respective cam slot. Similarly related faces or members may be provided for limiting the forward movement of the front mount.

Abstract: A lens barrel containing at least first and second movable lens groups and an operating member for shifting the movable lens groups along the optical axis includes a helicoid cylinder interposed between a first movable lens frame which supports the first movable lens group, and a fixed cylinder or a member whose movement relative to the fixed cylinder along the optical axis is prevented, whereby a shock externally imparted to the first movable lens frame is transmitted through the helicoid cylinder only to the fixed cylinder.

Abstract: An assembly includes a male member fitted in the bore of a female member in a rigid or slidable manner, with at least one of the confronting peripheral surfaces of both members being formed with a plurality of equally spaced projections which are positioned between the two members. These projections are of such a shape as to afford a low mechanical strength, such as for instance, triangular or trapezoidal in cross section, and contribute to eliminating any looseness in the fit between the assembled members. The projections may be cut or collapsed or otherwise altered under pressure by a face of the opposite member in which the projection carrying member is fitted during assembly thereby eliminating any clearance between the members with the resulting obviation of looseness.

Abstract: A varifocal lens assembly of simplified construction which essentially comprises a lens mounting for focusing adjustment, a second lens mounting and a third lens mounting cooperative with the second lens mounting for adjustment of the focal length and for correction of optical aberrations resulting from the displacement of the second lens mounting and an operating barrel for operating the first and second lens mountings, either independently or simultaneously. The operating barrel effects, when rotated, the focusing operation and, when axially moved, the zooming operation.

Abstract: Each exchangeable lens in a series of exchangeable lenses for use in single lens reflex cameras comprises a lens barrel including at least one lens and a diaphragm, a fixed index on the outer surface of the lens barrel, a diaphragm setting ring including f-number graduations ranging from a maximum f-number to a minimum f-number of the exchangeable lens, with the ring rotatable to a plurality of positions to align any one of the f-number graduations to an index so as to be set to a desired f-number. A first projection on the ring is spaced a predetermined first distance, common to each exchangeable lens of the series, from the minimum f-number graduation in the rotational direction of the ring. Thus, the amount of rotation of the first projection with the ring set to a desired f-number corresponds to the step-difference between the minimum and the desired f-number.

Abstract: A buffer or cushion made of a plastic material is interposed between an external device exposed to the exterior of a lens barrel and an internal mechanism within the barrel of a lens to absorb any impact applied to the external device and transmitted toward the internal mechanism and the lens unit. The external device may include an ornament ring and a barrel head sleeve and the internal mechanism may include sleeves for shifting the lens unit and members for holding the lens unit.

Abstract: The present lens system is capable of providing not only a zooming function over a relatively wide range, but also macrophotography. The zoom lens system includes a first lens group capable of varying the focal length without a loss of focus and a second lens group forming a master lens group. The second lens group is spatially displaced on the image side of the first lens group and includes a lens component movably mounted on the optical axis of the system that is capable of varying the focal length of the second lens group. The movable lens component in the second lens group has two positions which will provide the same final image plane for the entire zoom lens system, for example, a forward and backward position does not introduce any image plane deviations and permits an extension of the zoom range of the total lens system. The intermediate position of the movable lens component of the second lens group can be utilized for focusing in a macrophotography range.

Abstract: A diaphragm device in which a plurality of diaphragm blades are arranged in partly overlapping relation to one another. This diaphragm device provides a diaphragm aperture of a substantially elongated circle having its length extending in a specific direction, when stopped down beyond a given diaphragm aperture. More particularly, the diaphragm aperture is defined by a pair of arcs which oppose each other in a direction perpendicular to the specific direction passing through the center of the aperture and another pair of arcs which are disposed on the opposite sides in the aforesaid specific direction, while the distance of either one of the pair of arcs to the center of the aperture is shorter than the distance of either of the other pair of arcs to the center of the aperture. These pairs of arcs define portions of the inner peripheral edges of the diaphragm blades.

Abstract: In a photographic lens assembly having a plurality of lenses and held in a frame, an improved close-up focusing device in which an actuating shaft is rotatably provided in the frame and a transmission means connects the shaft and a mount holding one lens of the assembly in such a manner that the mount is moved relative to the frame in a direction parallel to the optical axis of the assembly by the rotation of the shaft, whereby close-up focusing is effected at, and independent of, any setting of the zoom lens assembly.

Abstract: A macro-photography varifocal lens assembly is provided for attachment to a camera body. The lens assembly can include a first lens group of negative refractive power and a second lens group of positive refractive power further supplemented by a master or auxiliary lens group of positive refractive power. One of the first and second lens groups are mounted for relative movement to vary the overall focal length of the lens assembly as the lens group moves across a predetermined range of movement. The image plane of the refracted image is continuously shifted from an initial predetermined position at one end of the range of movement towards the object and then away from the object to return to the initial predetermined position at the other end of the range of movement. This relative movement or shift of the image plane towards the object being sufficient to focus an image of an object in a macro-photography range.

Abstract: A control device for a varifocal lens system of a type which includes an optical system having a lens group movable along the optical axis thereof and in which the amount of the movement of the movable lens group necessary for focusing is varied in response to the focal length of the optical system selected by the zooming operation. The control device includes a member pivotable about a point in response to the focusing operation, a first movable member having a portion operatively coupled to the pivotable member, and a second movable member operatively coupled with the movable lens group. The first movable member is movable in a first direction perpendicular to the optical axis in response to the zooming operation for varying the distance from the portion of the first movable member to the pivoting point of the pivotable member.