Is there a hot shoe adapter that I can use to fire a 550EX with the standard pc sync from any camera. I have 2 and would like to use them as fill flash with my 4x5. I have tried one brand of shoe adapter with no luck. Does anyone know which terminals need to be shorted to fire a 550EX?

-- gary kessel (gkessel@troarch.com), March 07, 2002

Answers

You just need to short the larger, front center pin to the side of the foot contact to make the flash fire. Of course you won't have any flash metering & it will fire at full power or whatever power ratio you manually set it to.

Canon Speedlites are odd in doing what you are trying and may not work at all. Optical slaves with shoe mounts do this to some/most Canon Speedlites. They usually fire once and then lock up. You can free them up again by either turning the flash off and back on, or by pressing the red light/test button. After that it will fire once and then lock up again.

I have tested several Canon Speedlites and some behave this way and some don't, even from the same models. I had one 430EZ fail and another that worked fine as did a 420EZ. Both of my 540EZ's would not work.

Some people have reported that using tape to cover the other four contacts and keep them from shorting on the hot shoe adapter makes the Canon flash work correctly in manual mode. Others, like myself, haven't seen this work right.

-- Jim Strutz (j.strutz@gci.net), March 07, 2002.