just posted the article. It clearly states
that fast WIDE ANGLES also have the problem
and Nikon and Canon went to IF designs in them
BEFORE they addressed the teles.
JCO
> -----Original Message-----
> From: Frantisek Vlcek [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, September 11, 2002 5:31 AM
> To: J. C. O'Connell
> Subject: Re: Favourite K mount normal lens poll
>
>
>
> Tuesday, September 10, 2002, 11:09:55 PM, J. wrote:
> JCOC> it depends on the lens design. I was reading an old
> JCOC> photo magazine from the 70's about this problem.
> JCOC> Apparently the faster the lens and the longer
> JCOC> the focal length, the worse it gets for non
> JCOC> macro designs when you focus close up.
>
> But JCO, you weren't reading well enough :) This problem is mostly
> just for _telephoto_ design lenses, which are, without any IF or other
> means, severely compromised for close up focus (their effective
> aperture decreases much faster than a normal or wide lens design).
> Non-telephoto lenses like Gauss designs (most 80mm and 50mm lenses, as
> well as some longer) don't have such a big problem (they still are
> optimised for a given range, though). Of course a best
> 1:1 lens is a pure symmetrical lens, like your usual doppel-anastigmat
> for LF, where, ideally, all aberrations except chromatic aberr. are
> canceled out at 1:1 and 1:1 only.
>
> Good light,
> Frantisek Vlcek
>
