Camera with built-in electronic flash
First Claim
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1. A built-in flash camera equipped with an ever-flash exposure control system comprising:
- a brightness detector capable of measuring a level of brightness of a scene to be photographed;
a distance detector capable of determining a camera-to-subject distance;
a shutter which, for each photographic exposure, is capable of moving from a closed position to a fully open position, maintaining the fully open position for a predetermined period of time, and moving back to the closed position;
an electronic flash;
a memory containing a flash output correction value associated with each of a plurality of combinations of said scene brightness level and said camera-to-subject distance, said flash output correction values being established so that a proportional amount of light provided by the electronic flash in relation to said scene brightness level decreases as a function of increasing scene brightness level; and
a controller capable of retrieving the flash output correction value associated with the camera-to-subject distance and the scene brightness level from the memory and using the flash output correction value to determine the preselected time for triggering the electronic flash;
wherein the electronic flash is triggered at a preselected time while the shutter is one of partially open and fully open, wherein a degree of illumination provided by the electronic flash is maximized by triggering the electronic flash while the shutter is fully open, and wherein the degree of illumination provided by the electronic flash is progressively decreased by triggering the flash earlier during the shutter'"'"'s movement from the closed position to the fully open position.
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Abstract
An ever-flash exposure control system for a built-in flash camera controls a shutter to open and close so as to provide a standard exposure for scene brightness which are higher than standard scene brightness for which the shutter provides a full aperture to complete the standard exposure and triggers an electronic flash to provide illumination light at a time at which the shutter reaches an aperture according to a subject distance during exposure.
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Citations
6 Claims
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1. A built-in flash camera equipped with an ever-flash exposure control system comprising:
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a brightness detector capable of measuring a level of brightness of a scene to be photographed; a distance detector capable of determining a camera-to-subject distance; a shutter which, for each photographic exposure, is capable of moving from a closed position to a fully open position, maintaining the fully open position for a predetermined period of time, and moving back to the closed position; an electronic flash; a memory containing a flash output correction value associated with each of a plurality of combinations of said scene brightness level and said camera-to-subject distance, said flash output correction values being established so that a proportional amount of light provided by the electronic flash in relation to said scene brightness level decreases as a function of increasing scene brightness level; and a controller capable of retrieving the flash output correction value associated with the camera-to-subject distance and the scene brightness level from the memory and using the flash output correction value to determine the preselected time for triggering the electronic flash; wherein the electronic flash is triggered at a preselected time while the shutter is one of partially open and fully open, wherein a degree of illumination provided by the electronic flash is maximized by triggering the electronic flash while the shutter is fully open, and wherein the degree of illumination provided by the electronic flash is progressively decreased by triggering the flash earlier during the shutter'"'"'s movement from the closed position to the fully open position. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification