Seiko Koki Kabushiki Kaisha

Seikosha Co., Ltd.

Seiko Koki Kabsuhiki Kaisha

Shinji Nagaoka

Yuzuru Takazawa

Koji Sato

Kiyoshi Kitai

Yukio Nakamura

Hiroaki Ishida

Michio Kawai

Takeo Saito

Shogo Kato

Masuo Ogihara

Yoichi Seki

Nobuo Shinozaki

Hiroshi Yamazaki

Shigeru Tagami

Youichi Seki

Tomoo Yonemoto

Takashi Segawa

Hiroyuki Ishida

Koji Satoh

Eiichi Onda

Hiroyuki Saito

Yukio Morino

Michio Taniwaki

Yuji Nakajima

Shougo Kato

An auto focus camera produces a distance signal representative of the distance from the camera to an object being photographed. A first storage circuit stores comparative data to be compared with the distance signal, and a comparator circuit compares the distance signal with the comparative data. A second storage circuit stores lens extension amounts corresponding to the comparative data stored in the first storage circuit and outputs a lens extension amount corresponding to the specific comparative data selected by the comparator circuit. A focusing lens is positioned according to the output from the second storage circuit.

Auto focus camera

An auto-focusing device includes a light emitting element for emitting an optical beam to be projected upon an object, an image position detecting element for receiving the optical beam reflected from the object for outputting an image position signal, and range computing circuitry for receiving the image position signal and computing therefrom the range to the object and outputting a corresponding range signal. First and second level deciding circuits decide whether or not the computed data based on the image position signal is at a level validating the computation of the range signal. The level deciding circuits output a remotest or nearer-than-remotest signal dependent upon the computed image position signal if the computed data from the image position signal is not validated. A lens position setting device sets a lens position from either the range signal, the remotest signal or the nearer-than-remotest signal in accordance with the decisions of the first and second level deciding circuits.

Autofocusing device with improved distance focusing accuracy

A drive ring drivable by a stepping motor is normally urged by a spring to turn in one direction around a lens aperture. When not in use, the stepping motor is not subjected to the resilient force from the spring since the drive ring is locked against rotation by a ratchet wheel engaged by an engagement lever. The stepping motor is therefore not subjected to undue stresses and is prevented from malfunctioning. Consequently, focusing failures and exposure adjustment failures which could otherwise arise from malfunctioning of the stepping motor are prevented from occurring. In operation, a solenoid is energized to move the engagement lever out of engagement with the ratchet wheel, which is then freed to allow the drive ring to be turned by the stepping motor.

Motor-driven shutter for camera

An active rangefinder for use in a camera. The rangefinder has a light-emitting device, a spot light position detector disposed at a given distance from the light-emitting device, head amplifiers, filters having amplification function, synchronous detectors, integrators, an adder, a subtracter, a microcomputer, and an automatic gain control (AGC). The filters are connected to their respective head amplifiers each having an operational amplifier. The gains of the filters are controlled by the AGC according to the output signals from the synchronous detectors.

Rangefinder for camera

A method of driving the light-emitting devices of a multiple flash rangefinder for use in an autofocus camera in which the rangefinder includes a light-receiving device and an arithmetic processing unit that calculates the distance to the subject from the output signal from the light-receiving device. The light-emitting devices are lit up successively one at a time in such a way that each device emits momentarily and the series of operations is repeated several times.

Method of driving multiple flash rangefinder

A circuit for detecting back light comprises a time constant circuit including a capacitor selectively connectable in series with either a resistive element, or one of two CdS photoconductive elements used to measure the central and surrounding portions, respectively, of an object being photographed. Three switches separately conect the resistive element and the two photoconductive elements in series with the capacitor. A circuit generates pulses for a length of time governed by a time constant determined by the time constant circuit, and three separate counters store the pulses the number of which is determined by the time constant. An arithmetic circuit processes the pulses stored in the counters to determine the amount of back light present on the object.

Circuit for detecting back light

A range finder for use with a still camera and the like, projects an infrared light beam to an object and the light beam reflected from the object is detected by a split photosensor. The photosensor is made up of two photodiodes connected in opposite polarity relationship so that a differential photocurrent produced by the diode pair is amplified. The reflected light beam is tracked so that the photosensor provides a zero output, and the distance to the object is determined from the time needed to detect the zero photosensor output.

Range finder

A camera shutter has an automatic focusing lens operative when actuated to effect an automatic focusing operation. An actuating ring is normally placed in a non-operating region and momentarily shifted to an operating region during the automatic focusing operation. The actuating ring is sequentially displaceable in forward and reverse direction through the operating region to actuate the automatic focusing lens, and displaceable in the forward and reverse directions in the non-operating region without effecting actuation of the automatic focusing lens. A ratchet mechanism is coupled to the actuating ring for selectively locking and unlocking the actuating ring in the non-operating region in response to the displacement thereof in the forward and reverse directions. A bi-directionally rotatable stepping motor is connected to drive the actuating ring to displace the same in the forward and reverse directions.

A flashmatic device for cameras equipped with a programmed electronic shutter having sectors serving also as diaphragm blades, firing the flash at a suitable point in a phase of the shutter operation in which the aperture is gradually opened, to ensure synchronized flash shooting. Even in a case where a sector closing signal is produced earlier than a flash trigger signal, the flash is fired by means of a switch which is closed in relation with the sector closing motion to make flash synchronization possible under any condition.

Flashmatic device for cameras

An automatic film sensitivity setting device for cameras in which film sensitivity indicated in coded form on a loaded film package is automatically read in by electric signal terminals and introduced to an exposure control circuit as a parameter for the calculation and control of exposure, characterized in that the device is arranged to elect a predetermined specific film sensitivity in the absence of valid coded information of film sensitivity on a film case of the package, and in the case of an ordinary film package without the coded information, to elect a predetermined specific film sensitivity in the absence of information in any one of the electric signal terminals.

Automatic film sensitivity setting device for cameras

An automatic film sensitivity setting device uses part of electrical contacts provided on a film patrone of CAS system to produce from two-bit information a voltage signal indicating the film sensitivity index for the exposure control circuit of a camera. The device includes the circuit for setting the film sensitivity index manually.

Automatic film sensitivity setting device for camera

An active type distance detecting device wherein either a light emitting element or a light receiving element is operated to scan by a scanning means. A signal for driving the scanning means is interposed between pulse signals for causing the light emitting element to emit flickering light so that the former signal may not overlap with the latter pulse signals in order to reduce fluctuations of a load electric current.

Distance detecting device for a camera

An electromagnetically actuated shutter for a camera wherein automatic focusing and exposing operation are controlled by means of a single reversible stepping motor.

Electromagnetically actuated shutter for a camera

Light projected from an active lighting means to an object is reflected by the object, and a light spot is produced on a light-sensitive element by the light reflected from the object. The distance to the object is determined by detecting the position of the light spot on the light-sensitive element. The light-sensitive element for receiving the reflected light from the object has formed on a portion of a surface thereof an insensitive zone which has the same width or the same area as the light image produced by the reflected light and the light-sensitive element moves on an image plane in a certain relationship with the distance to the object whereby a change in a photoelectric output of the light-sensitive element is detected to detect the distance to the object.

Distance detector device

An active type range finder has a light-emitting element which is pulsatively driven to project light pulses on an object to be photographed. A photodetector element receives the light reflected from the object and produces a photoelectric output signal proportional to the amount of received light. A light-shielding member is scanned over the light-sensitive surface of the photodetector element in correlation with the distance to the object so that the light-shielding member successively shields successive areas of the light-sensitive surface from receiving light. An a.c. amplifier amplifies the photoelectric output signal, and an integrating circuit integrates the amplified photoelectric output signal and produces an integrated d.c. signal having a negative peak value indicative of the position of the scanning light-shielding member which corresponds to the object distance. Detecting circuitry detects the negative peak value and provides a corresponding detection signal indicative of the object distance.

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Yotsukaido, Japan

Shinji Nagaoka