Re: IR with a 500 mm mirror telelens?

[Eckhard Stephan <eckhard.stephan@xxxxxxxx>]

> >You correct focus with Konica, but not with HIE?

Depends on the filter. Since HIE has full panchromatic sensitivity,
focus corrections would be pointless as long as you're using a Filter
that lets considerable amounts of visible light pass through (like a
Wratten #25). If you focussed for IR, your subject would be out of focus
in the visible spectrum :-(... I do of course use IR focussing marks
when exposing HIE through visually opaque filters (87somethings and the
like).
Personally, I never had a focus problem with HIE. I DID, however, have
some trouble with Konica. Lately I tried some closeups with deliberately
narrow depth of field with a 210 mm telezoom lens. The Konica pics
(Wratten #25, no IR focus correction) were slightly, but noticeably out
of focus, whereas a parallel series on TMAX 400, which I shot with the
same lens, but a second body, was just fine. Of course closeups with a
telelens using large apertures are an extreme "worst case scenario"... 
> 
> HIE is so grainy you probably wouldn't notice the difference  ;-)
> 
Yep. Maybe I should pushprocess (N+2 ??) my Konica in Rodinal - more
grain, less focus problems!

> Cheers
> 
> Ben
> 

-- 
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*          Eckhard Stephan             * 
*          Freiburg (Germany)          *
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