FlashZebra wrote in post #4688600
To get both off camera you could go with what I call "hybrid triggering". Part basic sync, part Canon infrared.
You would need a hotshoe adapter and cord going to the 580EX II (cannot use the built in sync port as it does not support Manual/Master mode). Then have the 580EX II act as a master to the 430EX.
Everything would need to be manual mode and your sync speed will be limited to about 1/100 sec (or so).
Another inexpensive option (not hybrid triggering) would be a hotshoe adapter and cord to the 430EX and an optical slave on the 580EX II (optical slaves will not work on the 430EX). The advantage would be higher possible sync speeds (to your cameras X-sync limit).
Enjoy! Lon
The OP's flash is a 420EX, no manual mode. I was wondering the same question. From reading a few threads, most pro have the following setup: wireless transmitter (e.g. Pocket Wizard) to the master flash (580EX) which triggers the rest via Canon infrared. But this works only with flash that has manual mode. For the 420EX, we would need E-TTL mode on the master flash, and using wireless, you would lose that. An alternative would be to use a Canon off-shoe cord on the 580EX and set that up on a flash-stand. This way you will be able to use your master in E-TTL mode, which will trigger the 420EX correctly. Feel free to correct me if I'm wrong. I'm beginning to learn this stuff!