In cameras with «P» configuration or later shutter there is no ambient light measurement made. If a flash bar is in the shutter socket a flash picture will result regardless of the ambient light level.
On early cameras, an ambient light measurement is made during the flash delay period. Since the photocell aperture is a part of the shutter blades, the amount of reflected light reaching the cell will also be a function of focusing distance. the shutter electronics delays firing the flash lamp until the shutter has opened to the aperture established by the focus wheel. during this delay period, if the ambient light level is sufficiently high to cause triggering of the integrating circuits, the exposure will be completed and the shutter closed before the firing voltage reaches the lamp and the lamp will not be fired.
At the ends of the flash timing interval, the circuit energizes solenoid #1, the shutter closes, and the sequence proceeds as in the
If the bulbs in the flash bar are all used when the operator attemps to make a flash exposure, all of the previously described circuitly will function up to the actual firing of the flash lamp. Since there is no lamp to ignite, no flash firing current will be drawn.
There will be no output signal from the flash sequencing circuit, and an ambient light exposure will be made. On cameras with «P» or later configuration shutters, the result will be a black picture unless the ambient light level is high enough to give an exposure. this is caused by the fact that «P» and later configuration shutters have no integrating function as long as a flash bar is inserted in the socket. Early cameras have a twenty second