Re: IR with a 500 mm mirror telelens?

[Ben Kreunen <ben@xxxxxxxxxxxxxxxxxxxxxxx>]

At 10:32 AM 3/11/00 +0800, you wrote:
>If the lens has no other elements other than mirrors, you need no
>correction.  In practical cat lenses there are a number of glass
>elements.
>
>This leads me to suspect that the focus change would be negligible, but
>my cat lens has no IR marking and I've not used it for IR.
>
>Eckhard Stephan wrote:
> >
> > I think that some focus
> > corrections might be necessary, especially with Konica IR (I never used
> > any focus corrections for HIE with a #25 so far). Unfortunately, the
> > mirror tele hasn't got any IR focusing marks. So I'm not quite sure how
> > to focus... Any suggestions will be greatly appreciated.
>
>You correct focus with Konica, but not with HIE?


HIE is so grainy you probably wouldn't notice the difference  ;-)


Cheers

Ben

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