Very good mirror lens, color and sharpness just excellent. Hand held shoot not easy because focal length is 500mm and max aperture only f/8, but usable. This lens almost same light weight than any normal objective this means, convince to bring anywhere.
Rotating tripod ring can only apply to the earlier model 55B, the ring being absent on the 55BB.
I tried it once because I like the donut spread inherent to reflex lenses. But returned it after one roll. First of all, 500mm has narrow depth and is certainly not easy to focus. But the main reason is the image quality. It is very soft, totally out of my expectation. Consider the construction, the lens is light and the handling is requires large hand. All in all, I found my non-reflex lens has more crisp images and the focusing seems easier.
This is a popular "moon lens" because you can take great shots of the moon with it. There is no equivalent with a 4/3rds mount---the 4/3rds lens with the longest focal length is the Zuiko Digital (ZD) 300mm f2.8 ED lens. Since this Tamron is not a 4/3rds lens, you must operate your camera in either Manual or Aperture Priority mode and focus manually. This, along with its modest aperture, make it a poor choice for action shots that require fast shutter speeds and rapid changes in focus (although an E-1 equipped with a third-party split-prism focusing screen can help quite a bit with focus). Even still, I wouldn't recommend this lens if you plan to snap quick shots of moving critters owing to its manual focus.