Abstract: A filter device for a reflex optical system zoom lens having a front group of lenses and a rear group of lenses has filters in turret form located between said front and rear group of lenses and means for rotating the filters as a filter ring is turned. Since the diameter of a bundle of rays in the rear part of the zoom lens utilizing a reflex optical system is larger than the diameter of the bundle of rays between the front and rear groups of lenses, the size and weight of the filters is substantially reduced.

Abstract: A mechanism for extending a floating lens includes a rear group helicoid ring integral with a distance ring and supported rotatably on a stationary ring. A rear group lens frame which is threadably engaged with the rear group helicoid ring is guided for straight line movement as the rear group helicoid ring turns. A front group helicoid ring is rotatably supported on the rear group lens frame and a front group lens frame which is threadably engaged with the front group helicoid ring is guided for straight line movement as the front group helicoid ring turns. A guide plate is disposed outside the front group helicoid ring and is fixedly secured to the stationary ring. The guide plate is provided with a straight guide groove for guiding the rear group lens frame and a curved groove. A guide roller integral with the front group helicoid ring is engaged in the curved groove for turning the front group helicoid ring as the front group helicoid ring is moved back and forth with the rear group lens frame.

Abstract: A reflex zoom lens assembly includes a reflection optical system in which the full-aperture F number varies with focal length. A zoom ring of the assembly includes an aperture scale correlated to the focal length.

Abstract: A reflex zoom lens barrel comprising a front frame which carries reflex optical lens means having a positive focal length, a rear frame which carries transmission optical lens means having a negative focal length, zooming means for moving the front and rear frames in optical axial direction, to vary a focal length of a combination of the reflex and transmission optical lens means, and focusing means for independently moving only the front frame in the optical axial directions.

Abstract: A lens barrel for a camera body, having a first mount electrically connected to a first branch circuit and a first electrical contact connected to a second branch circuit, has a movable second contact which is retractable into a surface of a second mount on the lens barrel. A switching member is electrically connected to the movable second contact and is adapted to extend and retract the latter so that the movable second contact is electrically connected to the first contact of the camera body when extended, and is spaced apart therefrom when retracted. The switching member has a lower end portion having a third contact thereon, which electrically connects the switching member, the movable second contact and the second branch circuit with the first branch circuit when the movable second contact is extended.

Abstract: A lens exchange mount for a camera mount of a camera body has a contact pin supported in a lens mount to transmit lens data to a camera circuit during an automatic exposure camera operation. An "auto" and "manual" switching lever is connected to a fixing ring, and a switching contact is connected to the switching lever. When the switching lever is set to "auto", the switching contact electrically connects a first electrical contact, supported in the lens exchange mount, and the contact pin so that the latter is electrically connected to a camera circuit so that lens data are transmitted to the camera.

Abstract: A two-lens group type zoom lens having a high magnification factor and simple structure yet having smooth transfer between normal zooming and macrophotographing positions. The positions of the first and second lens groups are defined by a respective zooming cam slot and lead slot formed in a cam sleeve. For focusing, a focusing operation sleeve is rotated to determine the position of the first lens group along the optical axis. A linear slot is provided extending from a telephoto end position of the zooming cam slot parallel to the optical axis direction of the lens. Additional circumferential slots may be provided extending from the zooming cam slot and lead slot and a click-stop mechanism utilized to stop the zooming operation sleeve at the telephoto end position and macrophotographing range position.

Abstract: A lens mount barrel for flash photographing in which the relative positions of a flash source and a photographing lens are made variable and the photographic magnification or distance value can be set to preferred values within a general sequence of frequently-used numbers on a stopdown scale while simultaneously a click stop of the magnification scale is accomplished by a click stop on the stopdown scale. An operational sleeve and a stopdown sleeve cooperate with one another for focusing. A click stop mechanism is provided in the operational sleeve for click stopping the stopdown sleeve at positions corresponding to predetermined positions on the magnification scale.

Abstract: A close-up lens cylinder having at least an attaching cylinder for attachment to a camera body, an operating ring for operating an advance for focussing an advancing cylinder for a straight advance and a lens frame for supporting a lens. An advancing groove is divided into a circumferentially extending groove and a lead or cam groove such that by rotating the operating ring, initially only the lens frame is advanced with respect to the attaching cylinder without advancing of the operating ring and the advancing cylinder. After the advance is substantially completed, the operating ring and the advancing cylinder are advanced together with the lens frame.

Abstract: A lens barrel in which a distance ring is coupled to an aperture ring so that correct exposure can be obtained in flash photography. In the arrangement, a rotating member, which rotates integrally with the aperture ring, and the distance ring can rotate functionally with respect to each other through a fixed cylinder and an engaging member which can move in the direction of optical axis with respect to the fixed cylinder.