If my question does not give it away I will tell you that I am new to most of this.
I recently bought a C330 and have aquired a 55mm, 80mm and 135mm (all of them are black). I have shot some T-Max 400 test film to establish a modified ASA (Zone System approach), developed in T-Max 7 minutes at 20 degrees C.
The results of the test for the 55mm and the 80mm indicate a modified ASA for both of ASA 800.
Of all the reading I have done of this subject, a rating greater than the manufactuers ASA seems to be a very rare outcome.
Your comments would be most appreciated.