Being new to the land of 12-40 ownership, I'm a bit confused how the lens can be described as weather sealed when coupled to the EM5 Mk I. It's the first 'weather resistant' lens I've purchased, so have no previous experience to gauge from, or form an opinion. I was expecting something like a rubber 'O' ring on the bayonet interface, but nothing like that at all, at least on my copy (and there's no undercut for an O ring so I can't see it being part of the design). So how does a metal to metal interface keep out the watery stuff? Through necessity the lens to camera interface must have a clearance, and therefore a channel for moisture. Or does the bayonet somehow close up - although I can't see that happening otherwise the lens might bind to the camera flange. Any thoughts on this? From your own experience, is the pairing (12-40 f2.8 and EM5 MkI) ok in a light-ish shower? What I mean by that is not monsoon weather, which would be foolish by any standard.