Abstract: A range finder for an autofocusing device includes three photosensors or a photosensor including three section. An output signal from the line sensor representing a luminance distribution of the scene is A/D converted. A secondary difference of the output signal from the line sensor thus A/D converted is interpolated to compute and detect a zero-cross point. The zero-cross data obtained in this manner are stored, each in the form of interpolated zero-cross location data and polarity data within a single pixel. The zero-cross behavior signals obtained from two of the photosensors are successively shifted relative to the zero-cross behavior signal obtained from the other photosensor until a coincidence of the zero-cross location data and the polarity data of the three photosensors is detected. A range to the scene is computed from a total amount of shifting at the moment of the coincidence.

Abstract: A range finder circuit for a passive-type autofocusing device includes three line photosensors. Secondary differences of their output signals and zero-cross points of these secondary differences are computed and detected so long as these zero-cross points are those appearing when primary differences derived from computation of the secondary differences have absolute values larger than a predetermined value. The range to the scene is computed based on the amount of shifting of these signals into coincidence so that substantially no erroneous range finding occurs even when two objects composing the scene overlap each other. In a preferred embodiment also, signals from pixels of each photosensor are smoothed so that no erroneous range finding occurs even when the scene has on the surface thereof a fine repetitive pattern.

Abstract: A distance measuring device of camera for measuring distance to a pictured object includes pulse-driven first, second and third beam projecting elements. When a distance to the pictured object is long and beams of the beam projecting elements reflected from the pictured object are small in quantity or become nil, the first beam projecting element is pulse-driven until the number of light emission reaches a predetermined first maximum number of light emission, and the second and third beam projecting elements are pulse-driven until the number of light emission reaches a predetermined second maximum number of light emission which is less than the predetermined first maximum number of light emission. Because of this, when a distance to the pictured object is long and the beam projecting elements are pulse-driven to the predetermined first or second maximum number of light emission, it is possible to shorten a distance measuring time.

Abstract: A range finder for a passive type autofocussing device arranged so that light rays emitted from a scene to be photographed are picked up by three photosensors, output signals therefrom representing a luminance distribution of the scene are A/D converted, the zero-cross points of secondary differences of these digitized values are detected, zero-cross signals are compared with one of said three photosensors being selected as a reference and the zero-cross behaviors associated with the other two photosensors being successively shifted relative to said reference until a coincidence of the zero-cross behaviors associated with said three photosensors is detected, and a range to the scene is computed based on an amount that the zero-cross behaviors associated with said other two photosensors have been shifted until the coincidence is detected. Alternatively, said secondary differences of the digitized values are interpolated to detect the zero-cross points.

Abstract: A distance measuring apparatus has a light projector unit for generating a plurality of light pulses at predetermined intervals and for projecting them upon an object, and a light receiving unit for receiving the light reflected by the object and outputting a photoelectrically converted signal. A photoelectrically converted signal generated in response to at least a first light pulse of said light pulses is inputted to a comparator wherein it is compared with a predetermined voltage to judge which is larger. The gain of an amplifier or the light emission intensity of the light projector unit is adjusted in accordance with the signal level judged. After adjustment, the light pulses of principal emission following the pre-emission are projected and the reflected light pulses are photoelectrically converted by the light receiving unit. The photoelectrically converted signal of each light pulse is amplified by the amplifier and thereafter integrated.

Abstract: A photodetector element for use in a rangefinder of a camera comprises a first photoelectric element having a plurality of light receiving segments parallel to each other and adapted to provide a photoelectric output, and a second photoelectric element having a plurality of light receiving segments also parallel to each other with different available light receiving areas that increase from one side to the opposite side of the photodetector element to provide a photoelectric output that progressively varies from the one side to the other side of the photodetector element. The first and second photoelectric elements are electrically insulated from each other and so disposed that the light receiving segments thereof interfinger with spaces therebetween. The photodetector element provides two different photoelectric outputs from the first and second photoelectric elements whose intensities depend on the location on which incident light reflected from a subject falls.

Abstract: A light receiving element of a rangefinding device, for example for use in a camera, comprises a photoconversion light receiving element of which the light receiving surface is provided with a thin saw-toothed masking layer of aluminum directly deposited thereon by vacuum evaporation.

Abstract: An active-type autofocusing mechanism includes a light projector for projecting a light beam from a light source toward an object. A photo detector arrangement includes separate position-sensitive photo detectors disposed with equal spacing in opposite direction with respect to the light projector. A processor is connected to the photodetector arrangement for calculating the distance to the object.

Abstract: A camera shutter control apparatus comprises a detector for detecting the actual amount of opening of a camera shutter, comprised by a light emitter, a light detector, and a light controller for varying the amount of light passing therethrough from the light emitter to the light detector according to the detected amount of opening of the shutter. A controller controls the light emitter to emit a predetermined constant amount of light based on an output from the light detector. An operating device actuates the shutter in such a way to make the output of the light detector coincide with a signal representative of a predetermined shutter opening characteristic. The shutter is controlled to open and close following the predetermined characteristic defined by a shutter opening-closing program which is changeable according to the focal length of the camera lens.

Abstract: In a camera of the drop-in loading type having a film insertion opening formed at the bottom of the camera body, a device is provided for restricting a back lid, supported for pivotal opening and closing movement on the camera, to a partially opened position where the insertion opening is exposed and a guide slot is defined between the camera body and the back lid for allowing a film container with a film leader previously drawn out to be inserted therethrough. The restricting device can be released for full opening in order that the back lid is full opened to a position where the rear of the camera body is exposed to allow repairing an interior mechanism.

Abstract: An automatic winding camera wherein winding operations such as wind-up, rewinding, frame feed, etc. of a film are automatically performed.In the camera according to the present invention, when the absence of the film in a film running path in a camera is detected by a film detecting device during winding of the film, a control device controls a driving device for driving a film winding mechanism to operate until a film winding detecting device detects that at least a predetermined length of the film is wound up. With this arrangement, when the film is rewound into a magazine after the takings, the forward end portion of the film can be entirely received in the magazine, so that such disadvantages can be obviated that dust intrudes into and light falls into the magazine.

Abstract: A voltage dividing circuit containing a switching element is connected in parallel with a main capacitor of which a highly charged voltage is applied to a flash lamp for flashing. Only when the switching element is turned on does the voltage dividing circuit produce a divided voltage. The divided voltage is compared with a reference voltage. The result of the comparison is used for detecting the charged voltage across the main capacitor.

Abstract: A mode change-over device for a mode change-over device for a pre-winding type camera in which, after a loading of a film patrone in the camera and before the shooting, a pre-winding of the film is conducted to fully pre-wind the film on a spool and, when the pre-winding is finished, a mode retaining member is unlocked so as to release a mode change-over member thereby operating a mode change-over switch for a shooting mode, such as to allow an unwinding of the film in a frame-by-frame fashion for each shooting exposure, while the mode change-over member is charged by an opening of a back lid of the camera, the mode change-over device comprising; a counter adapted to operate in response to winding and rewinding of the camera; a retaining member for locking the mode retaining member when the back lid has been opened erroneously or accidentally; and a counter engaging member which prevents the retaining member from locking the mode change-over member when the counter is in the initial position, whereas, when th

Abstract: A pre-winding type photographic camera is provided with a mode changing mechanism for changing its operational mode between a pre-winding mode in which film is drawn out from a film magazine loaded in the camera and is taken up around the spool of the camera prior to photographing, and photographing mode in which the film is rewound into the film magazine by one frame each time the film is exposed.

Abstract: A shutter mechanism for a camera comprises at least one shutter blade, an electromagnet for holding the shutter blade in a blocking position where an exposure aperture is concealed and another electromagnet for returning the shutter blade to the initial and blocking position. The holding electromagnet is energized in association with the shutter actuating operation to permit the shutter blade to move, initiating exposure. The shutter blade in the course of movement to an unblocking position is forced to be returned to the initial and blocking position by the returning electromagnet when the latter is energized and the held therein by the holding electromagnet which has been deenergized, terminating exposure.

Abstract: A process for preparing petroleum resins having a low melt viscosity and satisfactory compatibility, characterized by firstly polymerizing a first feed portion comprising at least one chain conjugated diolefin having 4 to 5 carbon atoms and at least one monoolefinic unsaturated hydrocarbon having 4 to 10 carbon atoms in a proportion of 20 - 80 percent by weight of the monomers contained in the first feed portion and secondly polymerizing a second feed portion comprising at least one such chain conjugated diolefin and, if desired, at least one such monoolefinic unsaturated hydrocarbon, the first and second polymerizations being successively conducted in the presence of a Friedel-Crafts type catalyst in a polymerization reactor or reactors connected in series to each other.