Stuart Richardson , Aug 07, 2010; 08:33 a.m.
Have you considered using the Leica 2x APO converter? This will work, and though it is longer and slower, it still has superb optical quality. And it is a much more expensive option, but Leica will modify your 180/2.8 APO to the newer version which will work with the 1.4x converter. I asked them about it a few years ago (mine is the same older version as your own), but it was a couple hundred euros, if I recall correctly. It would probably be cheaper to sell your lens and buy a newer version.