Fuji Photo Optical Co., Ltd.

Oki Electric Industry Co., Ltd.

Saburo Numata

Shinichiro Fujino

Shinichiro Okazaki

Iwao Sagara

Hirohisa Shishikura

Fumio Kobayashi

Masanoshin Komori

Shin-ichiro Fujino

An excitation circuit for an electronic flash device for a photographic camera is arranged to energize the flashtube in a plurality of successive steps for each shot. In each of the successive steps, the flashtube is energized only for a time interval which is shorter than the time interval required by the flashtube to operate at its full power. This keeps the proportion of infrared radiation to a minimum.

Exciting circuit for electronic flash device

An automatic focusing apparatus of the type having an infrared light source for illuminating a subject wherein a position sensor for sensing infrared light reflected from the subject passing through two different portions of the picture-taking lens is provided to generate signals which represent condition of the picture-taking lens, that is, whether an image of the subject is in the best focus, front focus or rear focus. The position sensor comprises two position-sensing devices. By detecting the difference between the outputs from these two position-sensing devices, the condition of the picture-taking lens can be determined. A single position-sensing device can be used if AC signals are generated by a mechanical chopper in the forward position therefrom.

Automatic focusing apparatus

An auto strobe control circuit comprising a flash stopping signal generating circuit for measuring the luminance of an object exposed to light emitted from a flash tube by a photometric circuit, sending the obtained photometric value, film sensitivity information and aperture information to an operational amplifier to subject them to an arithmetic operation, and generating a flash stopping signal when the value calculated by the arithmetic operation, reaches a predetermined light amount. The photometric circuit essentially consists of a photoelectromotive force type light receiving element and a log-conversion diode connected in series with a constant-voltage circuit, and a temperature compensation circuit connected with the log-conversion diode. The photometric value is sent from a connection point between the light receiving element and the log-conversion diode to the operational amplifier. A voltage follower is positioned between the temperature compensation circuit and the log-conversion diode.

Auto strobe control circuit

In an optical instrument such as a photographic camera or an endoscope, the focus of an image of the object to be observed or photographed is automatically controlled based on the distance automatically measured. The distance of the object is automatically measured by use of a light source for illuminating the object, a photodetector, an image focusing optical system for focusing the image of the object on the photodetector, and an electric circuitry connected with the photodetector. The intensity of the illumination is periodically changed and the light reflected by the illuminated object received by the photodetector is measured. When the level of the output of the photodetector becomes equal to a predetermined level, a signal is generated to indicate that the brightness of the illuminated object has reached a predetermined level. Since the light intensity of the illumination at this point corresponds to the distance of the object, the distance is thus measured. According to the measured distance, a focusing lens is driven to automatically obtain a focused image.

Automatic focus controlling device

In an automatic exposure control device of digital information type for a single lens reflex camera, a sampling circuit for dividing pulses generated from an oscillator and a shutter release signal generating circuit are connected with a gate means having a function of an AND circuit. The gate means connected with a leading shutter blind control device and a normally turned OFF gate interposed between the oscillator and a clock pulse counter. When the gate means is turned ON by the simultaneous output of the sampling circuit and the shutter release signal generating circuit, the normally turned OFF gate is turned ON to initiate the counting of the clock pulses and the leading shutter blind is started to initiate exposure.

Automatic exposure control device for a single lens reflex camera

In a camera, a magnetic control device for controlling a shutter release mechanism or the like includes an electromagnet and a member to be attracted by the electromagnetic. The attracted member is mounted on an axle secured to a control lever. Between the axle and the attracted member, a resilient material is provided for allowing tilting of the attracted member around the axle so that the attracted member can be put into perfect face contact with the attracting face of the electromagnet even if the attracted face of the attracted member is at first not in parallel to the attracting face of the electromagnet.

Magnet control device for cameras

The amount of light to be produced in an electronic flash lamp apparatus, which is required to take a picture under proper exposure conditions, is predetermined depending on the object distance, the lens diaphragm aperture and the film speed. The actual amount of light produced in the electronic flash lamp apparatus is given as the integrated voltage of a portion only, of the discharge current that flows through the flash discharge tube. The electronic flash lamp apparatus automatically terminates the flash, when agreement between the predetermined and actual amounts of light is reached.

Method of and apparatus for automatic electronic flash lamp control

In a photographic camera with an automatic exposure control system, a voltage obtained by a light measuring circuit with reference to a reference voltage based on a film speed is divided into 1/n and (n-1)/n of the voltage. The scene brightness is measured while the diaphragm provided before a photosensor of the light measuring circuit is stopped down until the output voltage of the light measuring circuit becomes equal to 1/n of the voltage. After the output voltage has become 1/n of the voltage, the diaphragm is held in its position and then the shutter speed is controlled according to the (n-1)/n voltage.

Exposure control system for a photographic camera

In a digital exposure control device for cameras including an A-D converter connected with a light measuring circuit and a memory element connected therewith for memorizing the output of the A-D converter, a one-shot is connected between the A-D converter and the memory element so that the output of the A-D converter will be transmitted to the memory element only while the output level of the one-shot is high.

Memory locking means for digital exposure control device in cameras

A number of photoreceptors are arranged in a matrix along X-lines and Y-lines. An X-direction multiplexer and a Y-direction multiplexer are connected with the X-lines and Y-lines, respectively. Log-conversion amplifiers are connected at the input of the Y-direction multiplexer to log-compress the output of the photoreceptor before it is inputted into the Y-direction multiplexer. All the circuitry including the photoreceptors, multiplexers and amplifiers are deposited on a single chip to make an IC element.

Light measuring device

In a dual priority automatic exposure control camera in which the exposure control mode can be selected among aperture priority, shutter speed priority, program control and manual control, a mode change-over device is provided for selecting one of the exposure control modes. The mode change-over device includes a first signal generator which gives a first signal indicating whether the shutter speed is automatically controlled or manually selected, a second signal generator which gives a second signal indicating whether the aperture is automatically controlled or manually selected, and a mode discriminator connected with the two signal generators for discriminating the exposure control mode based on the combination of the first and second signals. The output of the mode discriminator is connected with an exposure control system to control the shutter speed and/or the aperture according to the discriminated mode of exposure control.

Mode change-over device for automatic exposure control camera

In an automatic exposure control camera in which exposure is controlled based on an output of an arithmetic unit, the F-value information of the taking lens of the camera in the arithmetic unit is compensated by use of a distance information from a distance detector, and the exposure is controlled based on the compensated F-value, whereby the exposure is compensated in close-up photography.

Exposure control compensating means for close-up photography

A single lens reflex camera having an interchangeable lens and provided with an exposure control device of the aperture size priority type is provided with a flash light control device in which the amount of light emitted by a flash light tube is controlled by a control circuit according to the film sensitivity of the film in the camera and the selected diaphragm aperture size. The selected diaphragm aperture size is input into the control circuit in terms of first information representing the displacement of the selected diaphragm aperture size from the full aperture size of the lens and second information representing the full aperture size of the lens.

Automatic flash light control device for camera

In a photographic camera provided with an electric shutter speed control circuit including a light measuring circuit in which scene brightness information is log-compressed and memorized by a memory circuit, the information is log-expanded by use of a decoder. A pulse generator is connected with a flip-flop group so that the pulses from the pulse generator are counted by the flip-flop group. The output of the flip-flop group is log-converted by a decoder connected therewith. The log-converted output of the decoder is compared with the output of the memory circuit by a comparator.

Exposure control device for photographic camera

In an automatic electronic flash light device, a light measuring circuit includes an operational amplifier, a photosensor connected between the positive and negative inputs of the operational amplifier and a diode for log-compression connected in a feedback circuit of the operational amplifier. The output of the light measuring circuit is thus log-compressed and the log-compressed output is applied to an operational circuit which gives an output for controlling exposure.

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Urawa, Japan

Saburo Numata