> > From: Jostein <[EMAIL PROTECTED]> > Date: 2005/12/19 Mon PM 02:39:17 GMT > To: [email protected] > Subject: Re: Re: Stacking lenses for macro. > > Quoting mike wilson <[EMAIL PROTECTED]>: > > >> Stopping down the 50mm to f/2 improves contrast, but > >> introduce more optical errors with small apertures > >> on the 200. This leads me to believe that the best > >> 50mm would be the one that is the sharpest at full > >> opening, whatever that may be... > >> > >> Jostein > > > > That is, unfortunately, likely to be one that has a > > smaller maximum aperture to start with...... 50/2.8? > > The only f/2.8 50mm I know is the macro. > I've been considering one of the f/2.0 variants.
That's the rascal. By definition, a lens with a smaller max aperture will be sharper - all other things being equal.... There is an f4 also, apparently. This might be an unsolveable problem with Pentax optics. You are, of course not limited to Pentax optics using this technique. I'll get my coat..... > > Once upon a time I had a A-50/1.7 which I thought to be fabulous for ordinary > use...:-) > > Jostein > > ---------------------------------------------------------------- > This message was sent using IMP, the Internet Messaging Program. > > ----------------------------------------- Email sent from www.ntlworld.com Virus-checked using McAfee(R) Software Visit www.ntlworld.com/security for more information
