Just out of curiosity - has anybody ever used/tested this monster? How does it compare to the old and new 500 for example or any of the mirror lenses? I know the MTFs are not that great. Does Zeiss have any plans to replace it with an APO version? I know that the old 500mm Tele-Tessar from the 60ies was just o.k. while the new APO version is excellent. Also the 1000mm mirror lenses are excellent, apart from price and out-of-focus characteristics. So - who has it? Anybody? And how is it really?