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1-5.
Synchronization
The camera has two synchronizing circuits; one with adjustable delay for Hash bulbs, and one
without delay for electronic flash. A precontact switch for each circuit is interconnected with the
shutter release. During a portion of the camera winding cycle the synchronizing contacts are closed,
but the precontact switches are closed only when the shutter release knob is depressed, and premature
firing is prevented. The synchronizing circuits, one side of which is grounded, terminate in synchro
outlet plugs on the rear of the camera top plate. The flash bulb outlet is identified by a bulb symbol,
and the electronic flash outlet by a lightning stroke symbol.
a. Flash Bulbs. Flash bulbs require a period of time between ignition and usable light output. To
provide this delay the synchronizing circuit must be closed before the first shutter curtain has started to
uncover the film aperture. The delay between closing of the circuit, and the entry of the first curtain into
the film aperture, must be varied in accordance with the shutter speed selected.
PRE CONTACT S1
MAIN CONTACT S2
SYNCHRO
ADJUSTING LEVER
SYNCHRO CAM
CONTACT ARM CAM
CONTACT ARM
Figure 1—13. Flash Bulb Circuit, Contacts Open.
(1) Delay mechanism (fig. 1-13). A synchro cam, on the shaft of the speed cam, positions the
synchro adjusting lever. The cam brings the lever closer to, or further from, the contact
arm as the shutter speed dial is adjusted.
Figure 1-14. Flash Bulb Circuit, Contacts Closed.
(2) Bulb circuit. The contact arm cam (fig. 1-14) on the main shutter roller assembly, rotates
when the shutter release knob is depressed. Rotation of the cam moves the spring-loaded
contact arm toward the synchro adjusting lever and closes the circuit. When the first shutter curtain has traversed the film aperture, the high point of the contact arm cam is resting
against the contact arm. This moves the arm away from the synchro adjusting lever and
opens the circuit.