Re: Medium format (was: plastic sheets

["Willem-Jan Markerink" <w.j.markerink@xxxxx>]

On  6 Jul 97 at 20:34, George L Smyth wrote:

> Jaap Los wrote:
> > 
> > I own a Nikkor 2.8/80-220 mm ED zoomlens, a beauty. I understand from
> > your mail messages, that I don't need to refocus this lens for IR
> > photography?? Mind you, there is a special IR focus indicator on this
> > lens, meaning, that a refocus is needed. Am I right? Or will the
> > ED-element sufficiently correct also for IR? Is there any difference for
> > using HIE, Konica 750 or SFX200/Agfa200 as regards to IR focus
> > correction?
> 
> Konica and Ilford really don't need correction, as they don't go as far
> into the IR as HIE. This means that visible light will probably dominate
> the scene.  Actually, I don't normally adjust focus anyway because I'm
> closing down to F8 or more and depth of field covers things pretty well.

I disagree with your Konica comment....the Konica Hexar, the only 
AF-camera that has an IR-focus setting, has two different 
corrections, one for 750nm (Konica) and one for 850nm (Kodak).
It might require *less* correction, but it still requires some 
correction. 



- -- 
Bye,

Willem-Jan Markerink


      The desire to understand 
is sometimes far less intelligent than
     the inability to understand


<w.j.markerink@xxxxx>
[note: 'a-one' & 'en-el'!]
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