Dptips :. Digital Photography Tips, Tricks, and Techniques

The flash trigger voltage is the internal voltage used inside the strobe/flash to trigger it’s circuit. To activate a flash the circuit needs to be closed (turned on) and the flash trigger voltage needs to flow thru the switch. Simple right? Yes, but what is usually the trigger? Well your camera is. Hot shoe or pc sync are built in switches of the camera that close the circuit when the shutter button is pressed.

So what? Well, most newer digital SLR cameras have a limit to how much voltage it can switch. Hence, there is usually a “safe” pc-sync or flash sync voltage that the camera must not exceed. Some flashes with a trigger voltage of say 250V is not intended to work with your Digital SLR with a sync voltage designated at 6V. This is important to know since most early model flash units had high trigger voltages.

I highly recommend you check out the “Photo Strobe Trigger Voltages” Website to see if your flash and camera are compatible before starting a fire Maybe not so bad, but you get the point.

PS. If you have a newer SLR and are thinking about the Vivitar flashes get the 285HV. This has a low triggering voltage and will work with most modern SLRs. The original Vivitar 285 will do some damage!