RE: Halo effects (was: Re: Maco IR 4x5)

["George L Smyth" <GLSmyth@xxxxxxx>]

> -----Original Message-----
> From: owner-infrared@xxxxx [mailto:owner-infrared@xxxxx]On Behalf Of
> Marco Pauck
> Sent: Saturday, January 15, 2000 7:31 AM
> To: infrared@xxxxx
> Subject: Halo effects (was: Re: Maco IR 4x5)
>
> Eckhard Stephan wrote:
> [...]
> > Besides that, I would like to have at least SOME halos...
>
> How about putting a Zeiss Softar (or a poor man's version avialable
> from other manufacturers) in front of our lens?
>
> Halo effects have nothing to do with infrared effects (such as
> white foliage). They are just 'incidentally' both separate features
> of Kodak's HIE. It would give us more freedom if we could control
> each of the effects separately depending on the subject.
>
> Sensitivity to the infrared part of the spectrum is a feature of
> the emulsion, i.e. the film. Halo effects should be limited to be
> a feature of the optical system, i.e. the lens!

The "halo" effect is due to the lack of an anti-halation layer.  The light
passes through the film, strikes the back plane, then goes back through the
film, reexposing it.  Using a lens to try to do this won't come close to
being the same thing.

george

---
Handmade Photographic Images
http://www2.ari.net/glsmyth/

*
****
*******
******************************************************
*  To remove yourself from this list, send:          *
*         UNSUBSCRIBE INFRARED                       *
*       to                                           *
*         MAJORDOMO@xxxxx                            *
*----------------------------------------------------*
*   For the IR-FAQ, IR-Gallery and heaps of links:   *
*  http://www.a1.nl/phomepag/markerink/mainpage.htm  *
******************************************************