>> It was either in the general Pentax lenses and accessories booklet or >> the manual of the 1.7x AF T/C that I read that the 50/1.7 is >> recommended for macro work with extension tubes; the 1.4 was >> recommended against.
> IIRC, that was deduced to be due to the flatness (or lack of) of the > focus plane. That was indeed the reason, although my memory (shaky at best - <g>) was that it may have been given in one of the extension tube manuals. Fred
