I read recently that the best lens ever produced was the 1960 Zeiss Planar 50mm f2 as fitted to the Contarex. I thought this was a pretty bold statement to make but he was a lens designer although I don't know whether was a novice or an expert. However since I have such a lens in a Contarex ( not a nice camera to use) and also an f2 Planar in a Kyocera Contax, I did some tests. In B&W ( I did not do any colour tests) the earlier Planar was markedly sharper at 20x16. I would say also sharper than my Summicron in my Leica M. Is there anyone who is a lens/glass expert who can say what lies behind the so called expert's statement. Is there some technical reason such as a rare glass that is too expensive to use in mass produced lenses ? Personally the differences don't matter at all to me but it was a provocative statement which is supported by my amateur tests.