I just upgraded to an R7 from an older T7i. I have two 430EX units that I'd like to use with the new camera. The manual has the following (emphasis mine):The following accessories cannot be attached directly to the multi-function shoe.Speedlite EL-...
So one of those two older flashes I mentioned in the original post just stopped working. To replace it I picked up a used 580EX II. It does indeed have that exact rubber seal at the base, and attempting to fully lock the shoe latch on the flash is ...
Thanks both of you for the quick replies. It would have been a lot easier to understand if it was noted the weather sealing was the point of compatibility rather than anything electronic. Also, I tried to accept either of the posts as the solution...