In the late 1980s I had several Tessar lens-ed Rolleiflexes, including a T. Of all I had, the T had the sharpest lens - I used Panatomic-X on a tripod and compared the negatives with a microscope, the subject matter was fine detail at infinity.
Originally Posted by ToddB
I've read but cannot verify that the Tessar used in the T had lanthanum glass to inprove on the corrections. The internals of the T may not be up to the standards of other Rolleis, but they are excellent by any standard. Use it and enjoy.
Too bad you can't get PKR-64 and really enjoy that lens...