I was fortunate enough to have acquired this lens a few weeks ago at the used camera show. It's getting expensive and often hard to find. Ordered a EOS conversion kit from Jim Buchanan and it only took about 3 minutes to do the nondestructive conversion. The converted lens fits perfectly on my 1D Mark II and infinity focus is precise and accurate. The only downside is that at infinity, the back of the lens will hit the mirror on the 1-Series and perhaps the 5D and 5D Mark II cameras.

Once you start taking pictures with this lens, you would understand why it has a cult following. At f1.2, depth of field is extremely shallow and getting critical focus is mostly a miss. When the focusing is nailed, even at f1.2, the lens is very sharp. From f2 on, the lens is phenomenally sharp. It's hard to find much difference between this lens and my Canon EF 50mm f1.2L, although the 50L does have an edge in sharpness at f1.2.

This lens is sharp at close distance as well as at infinity, which can not be said to a lot of lenses.

The construction of this lens is excellent. Mine is an older version that is all metal and glass. Later ones has a plastic focusing ring. Very heavy for a 50mm lens. Focusing is smooth like the Takumars. It really is a joy to take pictures with this lens, or just to play with it in your hand.