Coming back to the original question of this thread:

"Is there any database online of legacy lens T-stop ratings?"

Quote Originally Posted by Les Sarile View Post
The old lens reviews listed the T-number of the lenses. In this page a Rokkor 50mm f1.4 with a T-number 1.53, 28mm f2.0 with a T-number 2.25 and a 135mm f2.8 with a T-number 3.11. In these examples it doesn't seem significantly off.

This is interesting. I can't remember ever seen T-values indicated for still photography lenses.

What is also interestening is that these figures indicate the same T-factors as given for much more groups containing zoom lenses.