Flash unit having plural flashlamps

An electronic flash unit for operation in response to an applied trigger signal to illuminate a certain region, comprising:

• a trigger signal input, a first flashlamp and at least one additional flashlamp for illuminating said certain region, photometric means operative after application of a trigger signal at said input for developing at least two photometric output signals corresponding to light reflected from said certain region, one of said photometric output signals being developed in response to one integrated value of light and another of said photometric output signals being developed in response to another and higher integrated value of light, current supply means, and circuit means for applying currents from said current supply means to said flashlamps, said circuit means including first triggering means coupled to said photometric means for initiating operation of said first flashlamp in response to said one of said photometric output signals, second triggering means coupled to said trigger signal input for initiating operation of said additional flashlamp in response to a trigger signal applied at said input and at a time prior to triggering of said first flashlamp, first terminating means coupled to said photometric means for terminating application of current to said first flashlamp in response to said another of said photometric output signals, and second terminating means coupled to said photometric means for terminating application of current to said additional flashlamp in response to said one of said photometric output signals, said first flashlamp being thereby operative after said additional flashlamp and said first terminating means being thereby operative to terminate application of current to said first flashlamp in response to said another and higher integrated value of light reflected from said region after application of said trigger signal.