Electronic flash control apparatus
AssigneeNikon Corporation
InventorsHiroyuki Iwasaki, Keiji Osawa
Life of this patent
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Abstract
An electronic flash unit is caused to perform a pre-flash immediately before a photographing operation, and the quantity of light reflected by the subject during the pre-flash is measured by a flash metering unit. Based upon the output from the flash metering unit, a decision is made as to whether or not another pre-flash is to be implemented. Based upon the results of the decision-making, another pre-flash is performed if necessary. Thus, if the quantity of light measured by the flash metering unit during the pre-flash is too small or too large and a sufficient degree of accuracy is not achieved in the measurement, another pre-flash is performed to assure a high degree of accuracy in metering.
Claims10
An electronic flash control apparatus comprising:
- a flash metering unit that measures a light quantity of light reflected by a subject during a pre-flash performed immediately before a photographing operation;
- a decision-making unit that makes a decision as to whether or not another pre-flash is to be implemented based upon a signal output by said flash metering unit;
- a flash control unit that causes another pre-flash to be implemented based upon results of a decision made at said decision-making unit;
- and
- a flash output calculation unit that calculates an electronic flash output for the photographing operation based upon a signal output by said flash metering unit.
An electronic flash control apparatus comprising:
- a flash metering unit that measures a light quantity of light reflected by a subject during a pre-flash performed immediately before a photographing operation;
- a gain setting unit that sets a gain to be used to amplify a signal obtained from said flash metering unit metering the quantity of reflected light;
- a flash control unit that outputs a plurality of pre-flash commands to an electronic flash unit immediately before the photographing operation;
- a gain resetting unit that changes the gain set by said gain setting unit when a plurality of pre-flashes are implemented in response to said plurality of pre-flash commands output by said flash control unit;
- and
- a flash output calculation unit that calculates a flash output for the photographing operation based upon a signal output by said flash metering unit.
Dependencies are inferred from the claim text.