Okay guys I have a question for you. I have an assistant who has a 5D Mark II and a 6D. Both cameras when using a speedlight, either the 580 or 430, will not emit the AF focus assist beam. Both flashes work good on my cameras so the flashes are good. And to throw a wrench in everything, when put on the green mode, the AF light comes on, so it must be a setting. I crawled theough his settings and his speedlight custom settings allow for AF assist beam. I don't see anything stopping it. Any suggestions?