Do you indeed mean that all Summicron 50mm f/2 lenses are remarkably sharp center and edge at all apertures? Do you mean that they usually are? That a typical example is? Can you really stick a quality label on a whole series of lenses and expect one after the other to perform in precisely the same manner? Are all Meyer Primotars to be avoided or did some technical God in his finite wisdom create one magnificent Primotar somewhere along the line? Since I don't feel it's fair to keep you in suspense until the last line of the column, I'll confide that lenses can be very different indeed even from one sample to the next.