Anyone using one of these? Just some questions from some preliminary googling - The canon/alpha mount versions seem to have no aperture ring? Guessing these are purely electronic for aperture control and would need a compatible metabones/whatever style electronic adapter? Apparently the nikon version is one of those lenses for that mount that has no internal motor and is driven from the camera body, and the nikon version seems to have a manual aperture ring on it too. Anyone successfully used this as a pure manual lens on an m43 body?