Alan, The ST-E2 is basically a low power flash with an IR filter on it. So my guess is that you will be able to trigger a slave strobe with it, but as John pointed out, it will fire a pre- flash to trigger the expected EX slaves on the surroundings. I've seen some new IR "peanut" slaves that ignore this pre-flash, so you could disable the built-in slave on the strobes and plug those 'peanuts' instead.
Another option is to use the 550EX with an IR filter to trigger the slaves (the unexposed/developed slide film would do the trick). Just set it on (M)anual mode and use minimal power (1/128) to avoid any influence on your final picture. Manual mode doesn't fire a pre-flash. As an alternative you could use ANY cheapo manual-only hot-shoe mount flash unit taped with an IR filter (again) to trigger your slaves. Anything with just one contact on the foot will do the trick. Just be aware of some very old units with high voltage triggers that could fry your electronics. -regards, Gerard. * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
