Here's another newbie question. I have a just noticed something about the Technika Symmar 150mm (Schneider-Kreuznach) lens on my Technika V that I had not seen until now. There is an additional set of specs printed on the front element: The lens front says Symmar 1:5.6/150 (in white) and then 1:12/254 (in green). The f stops also have a duel set of numbering f5.6 to f45 (in white) AND f12 to f45 (in green). Is this some kind of duel purpose (convertible) lens? Thanks for your insight.