Hi davidhm
If the Zeiss 28-80mm you refer to is N mount (it will have a switch on the lens for AF/MF), then you cannot buy an adaptor to use it on your 5D MkII, however, even better, you can send it to Bo-Ming of Conurus who will, for a not insignificant sum, convert the lens to Canon mount.
He has developed software/firmware and a small microprocessor that is fitted within his meticulously manufactured and assembled canon mount conversion and this allows the lens to act as a native Canon lens with full autofocus, open aperture metering, EXIF info etc.
That is, of course, if the lens hasn't already been converted.
Hope that helps.
Regards, Piginho
