Abstract: The flash unit, particularly an electronic flash unit, is used with photographic cameras, and the like. The flash unit is provided with an electronic calculator which the photographer uses for calculating the numerical values of camera settings to be established for flash exposure, such as f-number, subject distance, and the like. The electronic calculator forms with the remainder of the flash unit a single camera accessory unit. Components of the calculating circuitry and of the flash unit circuitry are accommodated within a common housing and powered by a common power source. The display of the electronic calculator is located on the exterior of the flash unit, as is also the manually settable input stage of the calculator. The input stage comprises a pushbutton keyboard including digit and arithmetic-operation keys.

Abstract: A photographic apparatus is comprised of a plurality of adjustable units and a common digital display. The adjustable units and the common digital display are interconnected by information-transmitting circuitry. The circuitry includes selectors for selecting the unit whose setting is to be displayed on the common digital display along with an associated coordination symbol indicating which setting is being displayed.

Abstract: Operation of the release contact causes a capacitor in the light measuring circuit to be connected to the D.C. supply. The voltage across the capacitor is applied to the gate of a thyristor in the ignition circuit. Only when the voltage across the capacitor has reached a value for proper operation of the exposure control circuit which terminates the flash, is sufficient voltage applied to the gate of the thyristor in the ignition circuit to cause it to fire, thereby causing the flashtube to ignite.