I'm trying to set up a Panasonic-compatible flash on one of my G5s to act as the main TTL flash *and* set off a slaved Yongnuo 460-II as a fill flash (with the level set manually). With my macro subjects, optical slaving is not reliable--fairly often, the slave flash doesn't trigger. So far, trying to trigger the slave via a PC cable isn't working, and it seems to be the fault of my Canon-compatible hot-shoe/PC-port adapter. (I tested the slave flash with a non-TTL hot-shoe/PC adapter, and the flash fires--but of course I don't get TTL on the main flash that way.) So, for the moment, I'm (reluctantly) considering using a radio trigger. However, I really don't want to get into calculating manual flash exposure. I want the main flash to be TTL. So far, I haven't found a "TTL pass-through" radio trigger that's specifically for Olympus/Panasonic. Since I've been using a Canon-compatible TTTL flash cable to fire my main flash, I was wondering if a Canon-compatible TTL pass-through radio trigger would correctly the fire my main TTL flash *and* trigger the slave. Any help would be appreciated.