Tamron don't produce lenses for 4/3, only Olympus, Sigma and Panasonic do (under the Leica name) and their 4/3 lenses are the only ones which give you full automatic control for focus and aperture. You can mount OM, Nikon F mount, Pentax K-mount and many other lenses via an adapter but it's purely mechanical so you have to set the IS focal length, focus and aperture manually.
John