> > From: Kostas Kavoussanakis <[EMAIL PROTECTED]> > Date: 2005/09/06 Tue AM 08:57:10 GMT > To: pentax-discuss@pdml.net > Subject: Re: Film Lenses on Digital > > On Mon, 5 Sep 2005, Godfrey DiGiorgi wrote: > > > A D-FA50 macro lens is designed to be best at flat-field imaging, stopped > > down to f/8-f/32, in the near-focusing range. An A50/1.4 is designed for > > general pictorial use at wide apertures, and will not perform at its best > > at > > copystand distances. > > 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. m ----------------------------------------- Email sent from www.ntlworld.com Virus-checked using McAfee(R) Software Visit www.ntlworld.com/security for more information