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Bruce's Photo Blog
Bruce Foreman | September 2012

Using Old Flash Gear With Modern Digital Cameras

Someone sent me an email asking if older flash gear would work with our modern cameras using a hotshoe adapter. I hadn't heard this question in a few years so it gives me a bit of material for this column. Seems he has an older Norman professional flash unit and hated to see it sit idle in a corner. Most commonly this kind of unit connected to a female PC terminal on the camera using a cord with a male PC tip on one end and usually a male plug that looked a bit like a polarized AC plug on the other.

Well, most of our cameras today seem to lack the PC socket and the only connection for flash is the hotshoe. Simple hotshoe adapters with the PC terminal are available and they do work...

...Except for one thing...

Most older units had high “trigger” voltages, this is what goes into the camera and through the contacts on the shutter blinds or curtains, whichever your camera shutter uses. 5 volts is considered the safe limit on most of today's digital cameras and many of the older flash stuff ran a “trigger” voltage of around 230 volts into the flash connection.

The old “standby” of many a wedding photographer, the Vivitar 283 and 285 series, of which I still have a few of lying in a box somewhere, use a trigger voltage of 230 volts. This series is apparently still made and a redesign has brought that voltage down to a safe level, but if someone hands you one you have no way of knowing if you have a “safe” one or not. So just what do you risk?

“Fried” circuits in your camera for one thing. Wein, a company known for it's excellent photo “slaves” that can trigger a flash from the flash from another unit, came out with a “buffer” circuit that fits the hot shoe of your digital camera and accepts the hotshoe of an older shoe mount flash. It is supposed to “isolate” the camera from the older unit's high “trigger” voltage by sending a lower “trigger” signal into the camera. I ordered one and found it works...

...Sometimes...

Function on mine was a bit erratic (I've read the same complaint from others) so I kind of gave up on it. So what do we do? The cost of Canon flash and Nikon flash is kind of high.

For Canon I purchased a “dedicated” (to Canon) SunPak that wasn't too expensive and it worked very well for me. The question comes up, can we use the pop up flash on top to “trigger” other “slaved” flash units? The answer is unfortunately...No. The reason being our “newfangled” cameras use a “preflash” to measure some things for exposure and focusing distance, this preflash “triggers” the slaved unit prematurely before the camera shutter even opens. My solution to this was to mount my SunPak unit on top, put it in manual mode, and “dial in” the lowest manual power setting available. About 1/32 if I remember.

With the flash head tilted up this was enough to “trigger” a slave and in manual mode there was no preflash to contend with.

For anyone looking to acquire some “studio” flash to work with, Paul C. Buff's economy line “Alien Bees”, does have a safe trigger voltage of 5 volts.