I got some old flash units (e.g. Metz 30bct-3) that I won on eBay along with some older slr cameras. The flash units are in good condition. I thought of using them with my Canon 600D but heard about frying the camera's chip. Someone told about hotshoe pc sync and wireless trigger. I have no idea about these as I have just begin playing with dslr.

How do I get these old flashes working, either via wired or wireless, with my camera? What hardware would I need to accomplish this? What are the advantages and disadvantages of using an old flash unit with modern dslr camera?

Thank you!

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    \$\begingroup\$ botzilla.com/photo/strobeVolts.html you'll want this to check the voltages for your flash are safe to use on camera \$\endgroup\$
    – Dreamager
    Commented Sep 16, 2012 at 16:46
  • \$\begingroup\$ @Dreamager: The information is so cryptic. I don't understand it at all. \$\endgroup\$ Commented Sep 16, 2012 at 16:58
  • \$\begingroup\$ It takes about 4000 volts (at a very low current) to trigger a xenon flash tube (to get the arc started); before TTL control, the hot shoe was often a simple switch that either handled the 4KV directly or switched a relatively high-voltage secondary "safety" trigger (anything under 100V was considered "safe"; it didn't give a static-like shock if you touched the contacts). Anything more than 6V can potentially destroy your camera's flash circuitry, so using a safety trigger accessory as camflan describes is just good sense with older flashes. \$\endgroup\$
    – user2719
    Commented Sep 17, 2012 at 4:28
  • \$\begingroup\$ Duplicate? photo.stackexchange.com/questions/19204/… \$\endgroup\$ Commented Aug 11, 2016 at 17:27

3 Answers 3


Using wireless triggers is certainly one way to do this. Cheap triggers such as Cactus, Phottix, Pixl are all good choices, all the way up to PocketWizards. Or you can get some cheap hot shoe adapters with a cord.

Disadvantages are that you won't have TTL / Automatic flash mode. You'll have to set the power manually. check out Strobist on information for using flashguns in your photography. Start at Strobist 101, it will guide you through the basics of flash, other equipment you'll want, and how to get flashes working with your camera through cables and wireless triggers.

If you are looking to trigger using a cable or the hot-shoe, and the flash trigger voltage is unsafe for your camera's hot shoe - you'll need something like the Wein Safe Sync Hot Shoe adapter. This will give you a PC terminal AND a hotshoe connection. You'll be able to use a standard hot-shoe adapter on top of the Wein Safe Sync, or just stick the flash right on top. In addition, you could use the PC Sync port AND a flash or adapter on top, giving you a lot of options going forward.

  • \$\begingroup\$ You say "using wireless triggers is certainly one way to do this". Could you maybe eleborate on other ways to do this? Can a wired system also be used if the flash has an unsafe trigger voltage? \$\endgroup\$ Commented Sep 16, 2012 at 22:32
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    \$\begingroup\$ I've added a quick part about using a Wein Safe Sync to allow cabled use. \$\endgroup\$
    – camflan
    Commented Sep 16, 2012 at 23:01
  • \$\begingroup\$ Not all wireless triggers. Yongnuo RF-602 and RF-603 triggers are limited to 12V--they'll get fried as well. \$\endgroup\$
    – inkista
    Commented Apr 25, 2014 at 19:50

Readers who wish to use older flash units on modern digital cameras must be aware of the rather high voltages (often as high as 400V) present on the hotshoe connection, which can (and will) damage the electronics of almost any modern (digital) camera.

Those who are adept at electronics, might wish to consider the DIY optoelectronic isolator shown at this URL: http://www.carlmcmillan.com/optoisolated_adapter.htm


Older flashes, such as the Vivitar 285 that I got new in 1979, expose more than 300 volts to the hotshoe/PC-sync terminal. My old Nikon F was fine with that, as the sync terminal was just a physical switch that closed when the shutter opened.

Modern DSLRs are all electronic. And many (most?) electronic switches are designed for 5 volts maximum. If you put 300+ volts across it, it can damage the camera. Fixing this will cost lots of money.

B+H and all the other big camera stores sell "high voltage" adaptors that can handle the voltage of old strobes. There are also lots of DIY circuits if you are handy with a solding iron.

This is separate from the issue of wired vs wireless. Simply connecting some old flashes to your camera and firing the flash can cause expensive damage. Then you want to talk triggers. It should be obvious that a wired trigger (PC-sync cord, etc.) will simply transfer whatever voltage you have between the flash and body. So its essentially the same as connecting the flash to the hotshoe.

Some wireless triggers can handle the high voltage. Some of the less expensive "poverty wizard" units can not.

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    \$\begingroup\$ Can you point me to a product (wireless) which I can use to connect these voltage hungry flash units? Also, as @camflan suggested Wein Safe Sync Hot Shoe adapter, is it safe to be used with Canon 600D? \$\endgroup\$ Commented Sep 17, 2012 at 17:33
  • \$\begingroup\$ The Wein Safe Sync makes old flashes safe for modern DSLRs, so you'll be good with the 600D. The Cactus V folks claim that it works well with high voltage. I have not tried it, but that is their claim. I do have 4 Cactus V and like them a lot, and they are inexpensive. Be forewarned, the over voltage damage may not be instant, altho it will be permanent. So if I were to try an old flash with a Cactus V, I'd mark it and always use the same transceiver with the same flash. \$\endgroup\$ Commented Sep 17, 2012 at 17:46

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