Abstract: A position adjusting device for a camera optical unit includes a casing which is fixed within a camera for accommodating the optical unit therein, first and second supports provided between the casing and the optical unit for vertically and laterally pivotal movement of the optical unit with respect to the casing, a one-piece plate spring member having an integral laterally pressing piece for biasing the optical unit laterally and have an integral vertically pressing piece for biasing the optical unit vertically, and a pair of adjusting threads, threadingly engaged with the casing, for regulating vertical and lateral position of the optical unit against biasing forces of the vertically and laterally pressing pieces.

Abstract: Indication members provided around a central hole in a disk does not adversely affect reference surfaces to be clamped, and clear, stable indication is maintained. For this purpose, first and second optical disks having annular light transmissive disk substrates with a common central hole, one surface of each of which light transmissive disk substrates is provided with a reflection film, are attached to each other as one body with an adhesive layer interposed therebetween, such that the reflection films opposed each other, thereby forming a compound optical disk. Label members are provided from the reflection film side by printing or attachment on flat portions surrounding the central hole.

Abstract: A gear reduction unit, having first and second worm gears, includes a support member shaped such that a combined gear unit, having the second worm and a first worm gear coaxially formed therein, is held in an operating position by the first worm and a second worm gear engaging the second worm and first worm gear, respectively.

Abstract: A camera has an image format altering mechanism that includes at least one light buffer blade which is arranged to be inserted into and retracted from an aperture of the camera to thereby determine a picture image area. The camera also includes a camera back hinged to a body of the camera so as to be opened and closed, and an image format selecting member provided on the camera back to move the light buffer blade, the image format selecting member being movable between a position corresponding to a retracted position of the light buffer blade and a position corresponding to an inserted position of the light buffer blade. The camera is also provided with a buffer blade biasing member for biasing the light buffer blade towards one of the retracted position and the inserted position, so that the light buffer blade is located at the retracted position or at the inserted position when the camera back is opened, regardless of the position of the light buffer blade before the camera back is opened.

Abstract: A camera having a variable photographing aperture, including a photographing aperture size changing device that changes the size of the photographing aperture, and an exposure calculating device for calculating exposure factors including a diaphragm value and a shutter speed in accordance with the brightness of an object to be photographed. The camera further includes an exposure adjusting device which modifies the exposure factors when the photographing aperture is changed. The invention is also directed to a control method of a variable photographing aperture camera.

Abstract: An electroacoustic transducer having a diaphragm apparatus. The diaphragm apparatus has an annular diaphragm and a pair of outer and inner edges respectively conjoining with the outside and the inside of the diaphragm. Both edges have sets of pleats arranged continuously along the circumferential directions of the diaphragm but directed in opposite directions to each other. Each pleat, at least in the outer edge, comprises a bottom line extending from a boundary between the outer fixing area and the outer edge to a boundary between the outer edge and the diaphragm wherein an arc defined by the point of intersection of the inner end of the bottom line of any pleat in the outer edge and the second boundary and the point of tangency on the second boundary of a line through the point of intersection of the outer end of the same bottom line and the first boundary subtends a central single .theta..sub.0 and the position of the former point of intersection is given by the relation; ##EQU1## where .theta..sub.