Hey y'all. Have been messing with this and noticed it since the beginning.
At first I thought it was a flap to help make the eyepiece more flexible against your eye, but it's actually a rigid edge to the eyepiece. So then, my immediate thought was to test it with my weathercovers.
Turns out, the Think Tank Photo Hydrophobia weathercovers work great with this ridge, the rubber seal fits right into it and holds really well. So far it hasn't given me any problems in bad weather, and it works great overall. The ridge holds the rubber material far enough away on the bottom to prevent the rubber from going over the eyepiece sensor, so that hasn't been an issue. There's a little bit of flex on the bottom with this old beat-up 70-200 cover, but it was less bad on a newer one that had tighter rubber. With that flex, if you're in a downpour a slight bit of water may leak through, but then you can always use the plastic flap from the hydrophobia over the viewfinder and still see the EVF perfectly fine.
This was a big concern of mine when I found out the R5 eyepiece wasn't removable, so honestly now I feel a lot better about all that.
At first I thought it was a flap to help make the eyepiece more flexible against your eye, but it's actually a rigid edge to the eyepiece. So then, my immediate thought was to test it with my weathercovers.
Turns out, the Think Tank Photo Hydrophobia weathercovers work great with this ridge, the rubber seal fits right into it and holds really well. So far it hasn't given me any problems in bad weather, and it works great overall. The ridge holds the rubber material far enough away on the bottom to prevent the rubber from going over the eyepiece sensor, so that hasn't been an issue. There's a little bit of flex on the bottom with this old beat-up 70-200 cover, but it was less bad on a newer one that had tighter rubber. With that flex, if you're in a downpour a slight bit of water may leak through, but then you can always use the plastic flap from the hydrophobia over the viewfinder and still see the EVF perfectly fine.
This was a big concern of mine when I found out the R5 eyepiece wasn't removable, so honestly now I feel a lot better about all that.