Shutter / Flash Synchronization

From Photo-3d

(Much of this paraphrased from Alexander Klein, <100041.212 AT COMPUSERVE.COM>, and John Bercovitz.)

This topic applies to twin-camera setups, and refers to the difficulty of synchronizing the shutter mechanisms of two separate cameras. This is especially critical when using flash, due to the extremely short duration of typical flash units. Shutters on both cameras must be completely open when the flash occurs. Methods of addressing this include:

Table 3: Shutter Synchronization Methods

Method	Advantages	Disadvantages	Comments
Dual Cable Release	Inexpensive	Poor synchronization	The button must be pushed quickly to get reasonable sync (some hit the button). Sync may not be good enough to use flash
Spring-loaded
Air-pressure	Good for SLRs up to several feet apart
Solenoids	Most accurate of mechanical solutions		Suggest use of a storage scope for adjustment
Electrical	Good synchronization		For cameras with electrically-activated shutter

For flash synchronization, the following method has been tried with a camera with electric cable release (specifically the Minolta X-700)

(Credits to Dave Horn, John Bercovitz, and Kevin Skelton)

This has the effect of ANDing the two camera hot shoe switches, causing the flash to not fire until both shutters are closed. Kevin cautions: It was a little tricky getting the wires right, and I got zapped a few times because I forgot that the outer connections of cameras pc-jacks are already connected via the bodies and aluminum plate theyre mounted on.