I would love to buy one of these autofocus 500mm f8 lenses, but information about these lenses is sparse, and I haven't been able to find anything at all about if Sony made any changes to the lens other than re-branding it.
I understand that the Sony lenses are likely to be in better shape as Sony did continue making them until almost 2008 (?), but I'm also interested in knowing if Sony changed components like the lens motor or material used in manufacturing for either better or worse?