Canon Kabushiki Kaisha

Yasuo Isobe

Tadashi Ito

Fumio Ito

Soichi Nakamoto

An exposure control system for a photographic camera of the type provided with a shutter preselection automatic exposure range and a diaphragm preselection automatic exposure range, wherein various exposure control parameters are digitized and applied to a digital computer for providing either shutter interval or diaphragm aperture control signals. For exposure control in the shutter preselection automatic exposure range, there are provided a signal generator associated with the camera diaphragm mechanism, an analog-to-digital converter cooperative therewith for providing digital signals corresponding to ever varying aperture sizes as the diaphragm mechanism is operated from its fully open position, and a comparator connected between said computer and converter upon detection of coincidence of the signal from the computer with one of the signals from the converter to provide a diaphragm mechanism arresting signal. Further, the invention provides various types of non-contact device usuable as the diaphragm information generator.

Exposure control system for a camera having a digital computer

A camera having an exposure control device in which various photographing informations are converted into digital amounts and supplied to a digital operation circuit and the exposure is controlled by the output of the operation circuit. The camera comprises a digital-analogue converter for converting diaphragm informations from the operation circuit into analogue diaphragm informations, a comparison means for comparing the analogue diaphragm informations from a photographing lens with the analogue informations from the above digital-analogue converter, and an alternating switch which supplies the informations from the photographing lens to the comparison means for shutter preference photographing, and supplies the analogue informations from the photographing lens to the analogue-digital converter for diaphragm preference photographing. The output of the analogue-digital converter is supplied to the operation circuit, and the shutter preference and diaphragm preference photographings is made possible by the changeover of the alternating switch.

Exposure control device for a camera having a digital operation device

An electronic exposure control apparatus for a camera includes a setting means to set the exposure factor, a compression means connected to the setting means, for compressing the above-mentioned exposure factor logarithmically and an analogue-digital conversion means, being connected to said compression means, and generating a pulse number which corresponds to the output from the compression means. Also included is a first counter, which is connected to the output of the above-mentioned analogue-digital conversion means, for counting the pulse number from the above-mentioned analogue-digital conversion means, a pulse generating means, a binary counter having plural number of bits and connected to the output of the above-mentioned pulse generating means, wherein the counter counts the pulse number from the above-mentioned pulse generating means in association with shutter release, and the output of the counter is connected to the first counter for resetting the memorized content of the first counter. A coincidence detection means is connected to the output of the binary counter, wherein the means generates signals when the memorized content of the first counter is reset, and a control means is connected to the above-mentioned coincidence detection means, wherein the opening and closing of shutter is controlled by the signal from the above-mentioned coincidence detection means.

Electronic exposure control apparatus

An electronic exposure control apparatus for a camera includes a setting means to set the exposure factor, a compression means connected to said setting means, for compressing the above-mentioned exposure factor logarithmically and an analogue-digital conversion means, being connected to said compression means, and generating a pulse number which corresponds to the output from the compression means. Also included is a first counter, which is connected to the output of the above-mentioned analogue-digital conversion means, for counting the pulse number from the above-mentioned analogue-digital conversion means, a pulse generating means, a binary counter having plural number of bits and connected to the output of the above-mentioned pulse generating means, wherein said counter counts the pulse number from the above-mentioned pulse generating means in association with shutter release, and the output of the counter is connected to the first counter for resetting the memorized content of the first counter. A coincidence detection means is connected to the output of the binary counter, wherein said means generates a signal when the memorized content of the first counter is reset, and a control means is connected to the above-mentioned coincidence detection means, wherein the opening and closing of the shutter is controlled by the signal from the above-mentioned coincidence detection means.

An exposure control for a single lens reflex camera includes an adjustable shutter which is arranged to furnish a plurality of exposure times, and an adjustable electrical delay circuit which is operative to adjust the shutter to select the exposure time. An adjustable diaphragm is also included which is arranged to furnish a plurality of aperture sizes and is mounted into a lens and which further includes circuitry for receiving light from a photographing object through the diaphragm and converting it into electrical signal. A diaphragm determining device is connected with the diaphragm to select an aperture size, and which is connected to the receiving circuitry and further includes circuitry for detecting the adjustable aperture limit connected with the delay circuit to compensate the adjusted exposure time for proper exposure. A manually operated selector is included for adjusting the diaphragm determining device to insert the adjusted time. A storage capacitor is also included for memorizing the electrical signal of the receiving circuitry connected with the delay circuit when shutter operation is effected.

Exposure control device for a single lens reflex camera

A system for indicating photographic information which includes a circuit for converting an optical signal into an electrical signal. Comparing elements are provided for comparing the electrical signal with one of a plurality of reference signals having different levels, and electrical elements serve to produce an indication signal responsive to the output from one of the comparing elements. A plurality of luminescent components are connected to the signal producing element for turning-on in response to an indication signal. A plurality of indicating segments indicate the photographic information which the luminescent elements irradiate, the number of indicating segments being less than the number of luminescent elements and at least one of the indicating elements is selectively illuminated by more than one of the luminescent elements. The indicating segments have different colors to indicate different kinds of photographic information, whereby one indicating segment is capable of indicating two different modes of operation of the system. This is a continuation of application Ser. No. 437,621 filed Jan. 29, 1974, now abandoned.

System for indicating photographic information

An exposure control device for a single lens reflex camera includes an adjustable shutter which is arranged to furnish a plurality of exposure times, and an adjustable electrical delay circuit which is operative to adjust the shutter to select the exposure time. An adjustable diaphragm device is also included which is arranged to furnish a plurality of aperture sizes and is mounted into a lens and which further includes means for receiving light from a photographing object through the diaphragm device and converting it into electrical signal. A diaphragm determining means is connected with the diaphragm device to select an aperture size, and which is connected to the receiving means and further includes means for detecting the adjustable aperture limit connected with the delay circuit to compensate the adjusted exposure time for proper exposure. A manually operated selector means is included for adjusting the diaphragm determining means to insert the adjusted time thereinto. Storage means is also included for memorizing the electrical signal of the receiving means connected with the delay means when shutter operation is effected.

An automatic exposure control apparatus for a single lens reflex camera equipped with a shutter speed preselection exposure range and a diaphragm aperture preselection exposure range. When the apparatus is set for operation in the shutter speed preselection exposure range, the shutter speed preselecting dial is incapable of being set to its automatic adjustment position. When set for operation in the diaphragm aperture preselection exposure range, the diaphragm aperture preselecting dial is incapable of being set to its automatic adjustment positon.

Automatic exposure control apparatus which prevents simultaneous

In a single lens reflex camera, a lever responsive to operation of a shutter button initiates timing of an electronic shutter control a predetermined time interval before the shutter is actually opened. The predetermined time interval corresponds to the time elapse between the moment the shutter control changes the current which operates the magnet that holds the shutter open and the moment the magnet actually causes the shutter to close. After this predetermined time interval the shutter is opened, such as by running of the opening screen. After the measured shutter interval has ended, a current in the shutter control changes and operates on a magnet which has been holding the shutter open and causes the magnet to close the shutter, such as by releasing a closing screen.

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Kawasaki, Japan

Yasuo Isobe