If you buy a 580 EX II, you get a mini stand as an accessory. The stand is supposed to be used when the flash acts as a slave flash, instead of being located in the hot shoe on top of the camera's prism.
The same goes for the 600 EX-RT. There's a little stand supplied with that one too, and at a glance, it seems identical to the stand supplied with the 580 EX II. Well, even more careful scrutinizing will not reveal any difference between the two stands. But there is. The little hole, where the locking pin engages and prevents the flash and stand to separate, has a larger diameter in the stand for the 600 EX-RT. This causes the locking pin to maintain it's lock even when the lever above the flash's foot is released. Net effect - the mini stand can't be removed from the flash.
There's an emergency exit to this, since it's possible to push the locking pin back in by using a needle through the base of the mini stand, but it's a bit tricky to do. It's not funny standing there, when you are in a rush, unable to get the mini stand off from the flash, so it can be used on a camera again.
So my advise is to either make sure you don't mix the stands up with each other, or take a careful look at the stand for the 600 EX-RT, then enlarge the holes in your stands for the 580 EX II to the same diameter. There is no problem using the new stand with the old flashes, just the other way around.


