I have a 5D MKIII and recently got a 600EX. I understand that the 600 EX has radio built in, but the MKIII has no way to trigger the flash. My question: Is there some sort of trigger I can put on my camera that will trigger the 600EX without having an additional trigger on the flash. I'm looking for lower cost (so not interested in the Canon transmitter). I have been using Yonguo 602, but I thought it there was something I could put on camera only that would work better. The yonguo transmitter is a pain in the butt on my softbox.