Re: How to build a Tessar fro UV light (250...400nm)

From: Klaus D Schmitt (kds315_at_yahoo.com)
Date: 10/30/04 

Date: Sat, 30 Oct 2004 22:58:40 +0200

Thanks Brian,

you're very right. I just learned that. A Triplet would not be bad. I
just found some Ultra Achromatic designs in a patent database.
ther is one from 1968 showing execellent results with a triplet form!

I just can't have individual lens designs made in CaF2 and SiO2!
So I need a design which uses catalogue lenses....

Thanks,

Klaus

"brian" <brianc1959@aol.com> schrieb im Newsbeitrag
news:3c459ba.0410291459.7cb5c4c4@posting.google.com...
> "Klaus D Schmitt" <kds315@yahoo.com> wrote in message
news:<clt68q$crb$05$1@news.t-online.com>...
> > I would like to contruct my own UV Tessar or any other
> > achromatic/apochromatic lens for reflected light photography.
> >
> > Since I'm a complete newbie, any help would be appreciated!!
> >
> > Thanks,
> >
> > Klaus D Schmitt
>
> In that waveband you're pretty much stuck with CaF2 for crowns and
> SiO2 for flints. Forget about cemented groups since the cement won't
> transmit. The Tessar form won't work because of the cemented group
> and because it relies on a new-achromat for Petzval correction. A
> triplet or Petzval type design might be a good place to start. Watch
> out for tolerances, as they tend to be much more of a problem than
> with normal visible systems.
>
> Brian
> www.caldwellphotographic.com

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