Quote Originally Posted by AgX View Post
Yes. There are the older ones where you attach the lens and twist a breech lock and the newer ones where you attach the lens and twist the whole lens, and which is secured by that push button. Just two versions of the same bayonet locking.
The older version could in cases need a bit more fiddling, though that breech lock is typically self-arresting and only need a further twist for tight fit.
Yea, I prefer the older ones actually, I like the crew tightening at the end, it's always seemed a but more secure to me. The new lenses seem very loose on the EOS system, like there's always a little too much play, it should be snug.

Thanks