The focus ring on my Panasonic 20mm f1.7 lens doesn't work anymore. No matter what focussing setting, auto focus or manual, it's stuck at ~1m focal length and nothing will change it. The ring itself feels like it's rotating freely -- just smooth plastic against plastic -- as though nothing is catching internally. While on, the camera is scarily sluggish. I just moved so I'm afraid it was banged (I can't remember doing so though). Has anyone had this happen? Any thoughts on fixing? I'm not afraid to open the lens if I thought I could do something to help. As far as I can tell the actual optical assembly is well contained and the focussing assembly is accessible. With other native lenses focussing is just fine, so it isn't the camera itself.