MMF-3 Four Thirds adapter - so you can use any of the Four Thirds lenses but unless they are CDAF-compatible, AF may be a bit slow at 2-3 seconds
Canon full frame lenses
most of the Pro L series lenses are weatherproof
Canon EF-S lenses
I am not aware of any Canon EF-S weatherproof lenses
Nikon FX lenses
most of the Pro level lenses are weatherproof
Nikon DX lenses
usually a gold ring at the front of the lens suggests they are weatherproof and I am not aware of any DX lenses with this
many have a dust and waterproof rubber sealing mount but this only stops water getting into the camera and rear of the lens but water and dust may still be a major issue if you zoom in or out