Abstract: A method of moving at least one optical element of a plurality of optical elements of an image-forming lens system, wherein the plurality of optical elements are positioned along a common optical axis such that the lens system is in a ready-to-image position, the lens system having an object side and an image side. The method includes positioning the lens system such that no image may be taken, including moving the at least one optical element to a position away from the common optical axis and toward the image side, and moving at least one other optical element of the plurality of optical elements along the common optical axis toward the image side.

Abstract: A retractable lens system includes a plurality of optical elements. All of the plurality of optical elements are positioned on a common optical axis when the retractable lens is in use. A removable element of the plurality of optical elements is moved to a removed position outside of the common optical axis, and the removable element and at least one element of the remaining elements of the plurality of optical elements are moved rearward, respectively, when the retractable lens system is in a retracted position.

Abstract: An AF control apparatus includes a plurality of movable lens groups, each of which is movable along an optical axis for performing focusing independently, and a driving system for moving each of the movable lens groups A moving path of each of the movable lens groups during an autofocusing operation is defined so that a ratio of moving distances of the each of the movable lens groups is constant over an entire zoom range.

Abstract: An AF control apparatus for a zoom lens system includes a movable lens group serving as a zooming lens group and a focusing lens group in the zoom lens system; a focusing table which stores focusing data for the movable lens group; a zooming table which stores zooming data for the movable lens group, the zooming table having different data from the focusing table; and a driving device for moving the movable lens group in an optical axis direction of the zoom lens system according to data stored in the focusing table and the zooming table.

Abstract: A step-zoom lens includes two movable lens groups; a lens group support unit; and a cam ring having a cam groove. The cam groove includes a finite number of focal-length steps, so as to perform a focusing operation between infinite and closest photographing positions at each focal-length step. The cam groove includes a wide-angle mode section, a telephoto mode section, and a mode switching section. The closest photographing positions in two adjacent focal-length steps and the infinite photographing positions in two adjacent focal-length steps are adjacent to each other, respectively. One focal-length step of the infinite photographing position at a longest focal length in the wide-angle mode section is provided at one end of the mode switching section, and another focal-length step of the infinite photographing position at a shortest focal length in the telephoto mode section is provided at the other end.

Abstract: A lens moving mechanism includes a lens frame holding a lens; a guide shaft for slidably supporting the lens frame, the guide shaft extending parallel with the optical axis, a lead screw extending parallel to the guide shaft for moving the lens frame linearly via rotation of the lead screw; a pair of bearing arms provided on the lens frame spaced from one another in a direction parallel with the guide shaft; and a screw-engagement follower located between the bearing arms and provided separately from the lens frame, the screw-engagement follower provided with a screw-engagement portion engaging with the lead screw. The guide shaft is inserted in the bearing arms and the screw-engagement follower. The screw-engagement follower is integrally provided with an elastically deformable leg which abuts against an inner surface of a bearing arm to absorb play between the screw-engagement follower and the bearing arms.

Abstract: A cam mechanism for a lens barrel includes an annular member which is linearly guided along an optical axis, and having a cam follower on an outer peripheral surface; a cam ring having a cam groove on an inner peripheral surface including a photographing section and an accommodation section, the cam follower being engaged in the cam groove; and a biasing device for biasing the annular member forward to normally press the cam follower against a front cam surface in the cam groove. A rear end portion of the cam groove is open at a rear end surface of the cam ring to serve as the accommodation section, and the cam follower is disengageable from the front cam surface in the cam groove against a biasing force of the biasing device when the cam follower is engaged in the accommodation section.

Abstract: A lens barrel includes a lens frame for supporting a photographing lens group, the lens frame including a guide bore which extends in a direction parallel to the optical axis; a support barrel, wherein the lens frame can be inserted into and removed from a front opening of the support barrel; a rod receiving portion formed inside the support barrel; a bracket detachably attached to a front end of the support barrel; and a guide rod provided on the bracket for guiding the lens frame to move relative to the support barrel in the optical axis direction, the guide rod engaging with the rod receiving portion when the bracket is attached to the support barrel. The lens group frame can be taken out of the support barrel through the front opening when the bracket having the guide rods is removed from the support barrel.

Abstract: A method of moving at least one optical element of a plurality of optical elements of an image-forming lens system, wherein the plurality of optical elements are positioned along a common optical axis such that the lens system is in a ready-to-image position, the lens system having an object side and an image side. The method includes positioning the lens system such that no image may be taken, including moving the at least one optical element to a position away from the common optical axis and toward the image side, and moving at least one other optical element of the plurality of optical elements along the common optical axis toward the image side.

Abstract: An eccentricity-prevention mechanism includes a pair of lens-supporting rings for supporting a pair of lens groups, respectively; and a pair of positioning recesses and a follower projection formed on one and the other of opposed surfaces of the pair of lens-supporting rings, such that the follower projection engages with one of the pair of positioning recess to define a relative position of the pair of lens-supporting rings with respect to the optical axis, at a mutually close position and at a mutually distant position. At least three pairs of the positioning recesses and at least three follower projections are provided at different positions in a circumferential direction, so that eccentricity between the pair of lens-supporting rings is eliminated when all of the follower projections are concurrently brought into engagement with corresponding positioning recesses.

Abstract: A camera includes a lens support frame which supports a photographing lens group; an outer lens barrel which is provided on the front end thereof with a photographing aperture through which the lens support frame is moved; a lens barrier mechanism which opens and closes the photographing aperture of the outer lens barrel; a lens drive mechanism which moves the lens support frame in the outer lens barrel between a forward movement extremity in which the front end of the lens support frame is located in front of the photographing opening in an optical axis direction, and a rearward movement extremity in which the front end of the lens support frame is located behind the photographing aperture; and a barrier detection device for detecting the opening state of the lens barrier mechanism, based on an amount of movement of the lens support frame in the optical axis direction via the lens drive mechanism.

Abstract: A lens distance-varying mechanism for varying a distance between first and second lens groups includes a first lens frame; a second lens frame rotatable relative to the first lens frame; a relative-moving mechanism for moving the first and second lens frames to change a relative position therebetween on an optical axis when the second lens frame is positioned at each of forward and reverse rotation extremities thereof relative to the first lens frame; a differential linking ring which rotates together with the second lens frame; a differential ring which is rotated relative to the differential linking ring by a first angle of rotation greater than a second angle of rotation of the second lens frame relative to the first lens frame; and a biasing member, positioned between the differential ring and the differential linking ring, for absorbing a difference between the first and second angles of rotation.

Abstract: A zoom lens barrel assembly includes a first lens group including first and second sub-lens groups; a second lens group; a sub-lens group switching mechanism for moving the first or second sub-lens group away from the other in a short focal length photographing range, and toward the other in a long focal length photographing range; and a zoom cam mechanism having front and rear lens group cam grooves. The rear lens group cam groove includes first and second portions corresponding to the short and long focal length photographing ranges, respectively, the first and the second portions connected to each other via a discontinuous portion. The front lens group cam groove includes a non-linear portion which corresponds to the short focal length photographing range and provides a non-linear path, and a linear portion which corresponds to the long focal length photographing range and provides a linear path.

Abstract: A lens barrel includes front and rear sub-lens groups; front and rear sub-lens group frames for supporting the front and rear sub-lens groups, respectively; a lens frame shift mechanism for causing the front sub-lens group frame and the rear sub-lens group frame to move relative to each other to obtain the mutually close position and the mutually distant position; a first lens group positioning surface provided on the front sub-lens group frame for positioning the front sub-lens group by contacting with a portion of a rear surface of the front sub-lens group; and a second lens group positioning surface provided on the rear sub-lens group frame for positioning the front sub-lens group by contacting with a portion of a front surface of the rear sub-lens group.

Abstract: A light intercepting member driving mechanism includes light intercepting members which are each rotatable about a rotational axis parallel with an optical axis to open and close a photographing aperture; a drive ring which engages with the light intercepting member to open and close the light intercepting member in accordance with the angular displacement of the drive ring in forward and reverse directions about a rotational axis coincident with the optical axis; a motor which rotates the drive ring in the forward and reverse directions; a position indication portion provided on the drive ring to indicate the angular position of the drive ring; and a stationary detector which detects a passing of the position indication portion when the drive ring is rotated. The opening state of the light intercepting members is detected by the stationary detector and the position indication portion.

Abstract: A reduction gear mechanism includes at least first and second axes which extend parallel to each other; one of the first and second axes rotatably supports at least two gears arranged one after the other in the axial direction thereof, and the other of the first and second axes rotatably supports at least one gear, and the gears provided on the first and second axes being engaged with each other in such a manner that the gear supported on one of the first and second axes successively and alternatively engages with the gear supported on the other of the first and second axes.

Abstract: A lens drive mechanism includes first and second sub-lens group frames for supporting first and second sub-lens groups; a support frame for supporting the first and second sub-lens group frames; a first linear guide mechanism which linearly guides the first sub-lens group frame and prevents rotation thereof; a second linear guide mechanism which linearly guides the second sub-lens group frame, while limiting rotation thereof, at two extremities of rotation thereof; a lens frame shift mechanism for causing the first and second sub-lens group frames to move to the mutually close or distant position; and a linear displacement mechanism which integrally moves the first and second sub-lens group frames in the optical axis direction, in the mutually close or distant position. A linear guide clearance of the first linear guide mechanism is larger than a linear guide clearance of the second linear guide mechanism.

Abstract: A lens barrel includes a cam ring which is rotated about an optical axis to move a lens group in the optical axis direction via a cam groove formed on the cam ring, and a rotational ring which transfers a rotational motion to the cam ring. The rotational ring includes a rotation-transmission arm extending in the optical axis direction. The cam ring includes an engaging recess formed on an outer peripheral surface of the cam ring, and in which the rotation-transmission arm is slidably inserted to be movable in the optical axis direction, and an outer flange formed on an outer peripheral surface of the cam ring to form a slot penetrating therethrough in the optical axis direction between the outer flange and a bottom radial surface of the engaging recess so that the rotation-transmission arm is slidably fitted in the engaging recess through the slot.

Abstract: A lens shutter mechanism includes a support frame having a photographing aperture; at least three shutter sectors which open and close the photographing aperture via rotating axes which extend parallel to the optical axis; and at least three diaphragm sectors which vary an aperture diameter formed by the diaphragm sectors to restrict the diameter of the photographing aperture, independently from the shutter sectors, via rotating axes which extend parallel to the optical axis. The support frame is provided with rotational center portions spaced from each other at equi-angular intervals about the optical axis, the number of the rotational center portions being same as each of the number of the shutter sectors and the number of the diaphragm sectors. Each of the rotational center portions rotatably and coaxially supports a one of the shutter sectors and one of the diaphragm sectors.

Abstract: A cam mechanism for a lens barrel includes an annular member which is linearly guided along an optical axis, and having a cam follower on an outer peripheral surface; a cam ring having a cam groove on an inner peripheral surface including a photographing section and an accommodation section, the cam follower being engaged in the cam groove; and a biasing device for biasing the annular member forward to normally press the cam follower against a front cam surface in the cam groove. A rear end portion of the cam groove is open at a rear end surface of the cam ring to serve as the accommodation section, and the cam follower is disengageable from the front cam surface in the cam groove against a biasing force of the biasing device when the cam follower is engaged in the accommodation section.