Abstract: A lens assembly is disclosed in which the amount of movement of at least one lens unit is achieved by combining the amounts of relative movement of at least two barrels. A linear advancement barrel advances straight ahead relative to a fixed barrel. A first lens unit moves together with the linear advancement barrel. A second lens unit is located in front of the first lens unit along the optical axis. A third lens unit is located behind the first lens unit along the optical axis. A cam ring moves together with the linear advancement barrel along the optical axis and rotates around the optical axis. The cam ring has first and second cams that move the second lens unit and the third lens unit by amounts of movement relative to the linear advancement barrel.

Abstract: A film feeding apparatus of a camera using a film having two perforations in each frame. A perforation detecting lever has claws spaced at a predetermined distance apart from each other so that the distance therebetween is equal to the distance between the two perforations which are adjacent to each other across the boundary between frames. The perforation detecting lever engages the perforations and disengages therefrom in unison with an operation for feeding one frame to be performed after the proceeding frame is exposed to light. As a result, film feeding is allowed to proceed until both claws simultaneously engage two respective perforations in the film which occurs after the film has advanced one frame.

Abstract: A film feeding apparatus of a camera using a film having two perforations in each frame. A perforation detecting lever has claws spaced at a predetermined distance apart from each other so that the distance therebetween is equal to the distance between the two perforations which are adjacent to each other across the boundary between frames. The perforation detecting lever engages the perforations and disengages therefrom in unison with an operation for feeding one frame to be performed after the proceeding frame is exposed to light. As a result, film feeding is allowed to proceed until both claws simultaneously engage two respective perforations in the film which occurs after the film has advanced one frame.

Abstract: The operating mechanism according to the present invention is so constructed that an indexing mechanism moves by rotation of a reversible driving device in one direction and when the mechanism reaches a specified section corresponding to a selecting device, the mechanism drives a loading system, selected by the selecting device, by rotation thereof in the other direction at the section. The friction mechanism of a camera according to the present invention is so constructed that a spring for applying to a spool is attached to a spool driving gear. The electric film rewinding apparatus according to the present invention is so constructed that a planetary gear disengages from a driven gear in film rewinding gears by a driving force of a driving device. The driving control apparatus of a camera is so constructed that a single motor is driven for reversibly rotation in both of one direction and the other direction to execute only a necessary operation in loading and unloading a film, reversibly.

Abstract: An electromagnetic actuator suitable for use in combination with the mechanisms of cameras and the like. The electromagnetic actuator has a single electromagnet, and first and second armatures disposed opposite to the opposite attracting surfaces of the electromagnet, respectively. The first armature actuates a first operating lever for operating the shutter release mechanism of a camera, and the second armature actuates a second operating lever for operating the diaphragm of the camera. The first armature is separated from the attracting surface and the second armature is in contact with the attracting surface while the electromagnet is not energized. When the electromagnet is energized, the first armature is attracted to the attracting surface to actuate the first operating lever for releasing the shutter.

Abstract: A diaphragm control device for a lens exchangeable type camera includes diaphragm driving means providing a uniform speed over the entire diaphragm control range, so that accurate diaphragm control is achieved even in the vicinity of a fully open aperture value. The start position of the diaphragm drive means is determined such that the diaphragm control member of an exchangeable lens is engaged by a stopper to define a fully open aperture position in the course of return movement of the diaphragm drive means to the start position. A coupling spring coupling the diaphragm drive means with a diaphragm control member of a camera body as an integral unit is deformed to allow separation of the diaphragm drive means from the diaphragm control member of the camera body so that the diaphragm drive means can return to the start position after the engagement of the stopper with the diaphragm control member of the exchangeable lens.

Abstract: A depth-of-field preview apparatus for a single lens reflex camera is provided with a display circuit responsive to a preview display signal generated by a control circuit with at least one of first and second switches being closed. The first switch is closed when an operating member is operated to an operated position and opened when the operating member is released to return to a non-operated position under a spring bias. In response to the closure of the first switch the control circuit generates the preview display signal and an electromagnetic device causes a diaphragm stop-down mechanism to stop-down a diaphragm. When the diaphragm is stopped-down to a preset aperture size, another electromagnetic device stops the diaphragm stop-down mechanism to set the diaphragm to the preset aperture size and at the same time closes the second switch.