Abstract: In an electronic flash device for use in a still camera, a calculation circuit means calculates a ratio of the amounts of light to be emitted by a plurality of flash light tubes on the basis of color temperature information and control circuit means controls the emission of light of the respective flash light tubes in such a manner that the ratio of light amount emitted from the respective flash light tubes corresponds to the ratio calculated by the calculation circuit means.

Abstract: In an instrument such as an electronic desk-top or pocket calculator, an exposure meter or the like, having a plurality of data-inputting switches in the form of a pushbutton switch, key switch, pressure or touch sensor switch, a control switch is provided for preventing inadvertent change of data stored or registered in the instrument. To this end, gates are interposed between the data inputting switches and a data storage member in the instrument. The instrument could alternatively include a microcomputer programmed to change its stored data in response to the operation of the input switches and to be prevented from changing the data upon operation of the control switch.

Abstract: Disclosed herein is a light measuring and control data calculating device for use in a photographic enlarger. The device comprises first light detecting means for detecting the amount of light emitted from a light source, second light detecting means for detecting the emitted light amount at a position on the surface of an easel through the optical system and an original film in the enlarger, setting means for manually setting a preliminary desired amount of light to be emitted from the light source and calculation means for calculating an actually desired amount of flash light to be emitted from the light source for obtaining a desired total amount of the exposure light on the surface of the easel for making a suitable exposure on the printing paper to provide a best print.

Abstract: A light measuring device includes one or more photodiodes, which generate current in relation to the received light, and at least one capacitor for integrating the generated current. The amount of charge stored in the at least one capacitor at the completion of the integration is roughly detected by the number of capacitors used and/or the voltage across the capacitor. A current source capable of producing different levels of current in accordance with the detected amount of charge is provided for changing the amount of charge stored in the at least one capacitor. The time needed to change the amount of charge stored in the at least one capacitor is measured so as to obtain the value of total amount of the change in the charge stored in the at least one capacitor and to thus obtain the value of the received amount of light intensity.

Abstract: A system disclosed is for calculating a light information value, such as an f/stop number, which is determined by a number of light sources such as strobes. The system calculates an optimum f/stop number for each of the strobes as the strobes are fired one after another and, at the same time, calculates after each firing of the strobe an optimum f/stop number for the strobes which have been fired. The optimum f/stop number for the plurality of strobes fired at the same time is displayed.

Abstract: An exposure indicator for use in a light meter includes a light measuring device including a light receiving element for producing an electrical signal representing the brightness of the light received by the light receiving element, and a circuit for changing the electrical signal from the light measuring device by an amount determined by a setting mechanism. A first indicator is provided for indicating a value of an exposure parameter, such as an aperture F-stop value, based on the changed signal, and a second indicator is provided for indicating a density of a reproduced film in accordance with the electrical signal from the light measuring device and the changed signal.

Abstract: An exposure amount indicating arrangement for use with a photographic printing apparatus or the like, which includes an exposure amount setting section for setting values corresponding to desired printing exposure amount, an elapsed exposure amount output section for successively outputting values corresponding to elapsed exposure amount from starting of the printing, a calculating section for working out a ratio of the elapsed exposure amount to the set exposure amount, and an informing section for visually or acoustically indicating the ratio of the elapsed exposure amount to the set exposure amount, based on the value worked out by the calculating section.

Abstract: A trichromatic colorimeter for obtaining the CIE chromaticity coordinates for an object to be measured. By utilizing a logarithmic compression type light measuring circuit, a higher accuracy and measuring range are obtainable in comparison to prior art linear light measuring type colorimeters.

Abstract: A light meter includes memory units for storing light intensity signals obtained from a light intensity measuring device. A segment displayer is provided for displaying a value of exposure parameter based on selected one of the light intensity signals obtained from the memory units and light intensity measuring device. A dot displayer is also provided for displaying a value of exposure parameter based on respective one of the light intensity signals obtained from the memory units and light intensity measuring device.

Abstract: A photographic spot measuring device for determining a film exposure for an object relative to a film latitude and which is capable of reproducing various parts of the object with possible respective densities between a pair of density limits is disclosed. The device operates by selectively measuring the luminance of a desired part of the object within a limited acceptance angle and producing a light measuring signal in response thereto and generating a limit exposure signal to effect an exposure of the film in which the measured part of the object is reproduced on the film within the density limits.

Abstract: In a photographic light measuring device, a light output signal representing light reflected from an object to be photographed is converted into digital signals. At least first and second setting means generate respective first and second digital set signals which are respectively variable in response to respective manual operations. Photographic exposure data signals are generated using the digital light signal and the first and second set digital signals such that indicating means can selectively indicate data commensurate with the first and second digital set signals.

Abstract: A color meter for measuring the respective intensity of the blue, green and red regions of an illuminating light source to provide the photographic information according to the measured value. The present invention provides an appliance, which directly provides, as the final output, the light balancing factor or the color compensating factor according to the necessary one from among the measured informations of the light intensity of each region of blue, green, red and an information determined according to using film, video image pickup tube, solid image pickup element, etc. and of which the operation is simple and the correcting filter can be simply and quickly determined.

Abstract: The disclosure is directed to an improved light measuring device which is used in flash photography for measuring a preliminary flash light to obtain camera exposure information for photography under a primary flash light. The device is so arranged as to preliminarily obtain informations of light amount contributing to photographing, with respect to each portion or area of a scene to be photographed or object field, in taking photographs with the employment of the auxiliary light.

Abstract: An exposure control system includes a device for measuring an intensity of the ambient light, three controllers for controlling three factors of exposure time, aperture size and amount of flash light to be emitted, and a device for setting three pieces of information of film sensitivity and any two of the above mentioned three factors to govern the corresponding two of the three controllers. A calculator is provided for calculating the remaining factor. The calculated value is used for governing the remaining controller. Of the three pieces of information set in the setting device, two pieces can be introduced in a form of a ratio.

Abstract: With an exposure meter usable in both reflected light mode and incident light mode, the exposure meter is capable of displaying a value measured in reflected light mode with a reflected light mode attachment mounted on the exposure meter, and a value measured in incident light mode with an incident light mode attachment mounted thereon.

Abstract: A system disclosed is for calculating a light information value, such as an f/stop number, which is determined by a number of light sources such as strobes. The system calculates an optimum f/stop number for each of the strobes as the strobes are fired one after another and, at the same time, calculates after each firing of the strobe an optimum f/stop number for the strobes which have been fired. The optimum f/stop number for the plurality of strobes fired at the same time is displayed.

Abstract: A light measuring device for use in photography and a method therefor is disclosed, in which the quantity of light during a time interval when the flash light is present is measured and also the quantity of light under the ambient light only is measured for obtaining various exposure information for photography using the flash light.

Abstract: An exposure information indicating device for use in photography includes a detecting section for detecting various known information values such as brightness or luminance of an object and film sensitivity represented by ASA number, a calculating section for calculating an unknown exposure information value such as f/stop number and a display section for digitally displaying the calculated value.

Abstract: An exposure time controlling system includes a circuit for producing an APEX shutter speed signal which is applied to a first discriminator for briefly classifying the APEX shutter speed signal into four classes and also to a second discriminator for sub-classifying the APEX shutter speed signal. A pulse generator is provided for producing pulse signal having a frequency determined by the class and a counter is provided for counting the pulses for a number of times determined by the sub-class. A shutter mechanism is opened when the counter starts to count and is closed when the counter finishes counting the pulses.

Abstract: A digital light measuring device capable of measuring a flash of light generated by a separate source device, irrespective of trigger modes of an electronic flash selected in advance, which comprises means responsive to an incident light intensity for producing an input commensurate thereto; means for processing an output to form a digital signal indicative of a result of the light measurement; means for detecting the beginning of change in the output of the producing means caused by a flashing to generate a start signal for making the processing means begin the processing operation; means for controlling the operations of the processing means in a programmed sequence, and, where necessary, means for directing the controlling means to start the programmed sequence when a code-trigger mode is selectively chosen for the trigger mode of the electronic flash.