Due to a variety of problems we have encountered, we do not recommend using Olympus lenses for video use with Panasonic micro 4/3 cameras/camcorders. Rent at your own risk.
The top supertelephoto in the Olympus line, the 300mm f/2.8 provides the equivalent of a 600mm lens (35 full frame equivalent) in a lens small enough to be handheld, at least for a while. With 3 ED elements chromatic aberration is virtually eliminated and the lens is remarkably sharp.