I currently own a Yongnuo 580 II but I am thinking about upgrading to a 430ex II or a 580ex II. I have done some research an realize the big difference in the 2 is flash power and the fact you canuse the 580 as a master. What I dont understand is, when using the 580 in master mode, does that mean the flash has to be mounted on the camera or can it be used as a master off the camera as well? I dont see the point in buying a 580 if all your going to do is keep it on the camera to use as a trigger, why not just buy some radio slaves and 430ex. Am I missing something here? Basically I use my speedlite in full manual mode currently but I want to start becoming famililar with E-TTL mode and controlling different groups of flashs from my 7D. With the yongnuo I have now, willt he 580ex still work as a master with it or does it have to be a Canon slave? sorry for allt he questions!