Can I add a related question to this old thread? If it gets missed I'll re-start it as a new thread.
I am interested to know if there are any significant differences in performance, robustness, build-consistency, etc between the TC-14E and TC-14EII? Various internet sites say they are optically identical. I'm not sure if that extends to identical coatings. The TC-14E sells used for a much lower price than the TC-14EII, and I'd be interested to know if this is due to a known weakness of the TC-14E, superstition, or the common belief that a newer version must be better. My main use will be with the 300 mm f/4 AFS on a D810.
A second, more obscure question: The main difference seems to be in the materials used in construction. Does anyone know whether either version has problems in very cold conditions (say, down to -20C)? I notice that Oivind Toien has posted some very nice winter photos from Alaska indicating use of the TC-14E, elsewhere on NG.
Thanks - John