Re: About filter reflection factors....

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

On 12 Nov 96 at 0:38, Vaughan Bromfield wrote:

> >So what I need is the spectral reflection coefficient of HIE, as well
> >as the spectral sensitivity of the OTF flash sensor. That isn't much
> >to ask, is it? <grin>
> 
> If you have the filter between the film rails then the otf sensor won't be
> seeing the film, it'll be seeing the filter, won't it?

Yep, but to estimate the difference, I must have the reflection 
coefficient of both filter and film....;-))
Only the first doesn't help much, since I have no reference of what 
it should be with normal film.

And 'a' reflection coeffient is also not enough, I need it for
visible and IR, the latter if I use an IR filter in front of the
flash as well (you can't just pull the BTFR filter off when the
camera is still loaded with film). The only data known (for EOS) is
for no BTFR filter (aka bare reading....:-)) and a filter in front
of the flash. 

Oh well, I guess I'll just have to bracket and reverse calculate the 
reflection coeffient difference....8-))

--
Bye,

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      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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Topic No. 2