Re: Filters

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

On 10 Sep 98 at 17:43, James Lewis wrote:

> I've tried 87 and discovered I prefer the 25. IR effect is more pleasing with
> the 25. And you don't have to shoot blind. (The 87 passes NO visible light.
> It's like a piece of black glass.)

That is why the BTFR (between the film rails) filter solution is so cool:

Pro:
- - no viewfinder darkening/blackout (would even apply to the 
non-opaque #25/70/89B)
- - no more endless switching of filters between composing and exposure
- - no more switching of filters while swapping lenses
- - all strange filter constructions are solved (my Sigma 8mm uses 
internal filters, requiring to split front and rear of the 
lens(!)....same would apply to rear-slot high end teles, as those want 
to be focused with at least a clear filter mounted
- - add my addiction to shoot in very hostile environments (steep ski 
slopes, -20C and a wind speed that topples you over), and any bare 
finger fiddling with filters is a night mare.

Contra:
- - it requires a dedicated IR body, as the filter is semi-permanently 
mounted (clear office tape in my case, nothing exotic nor damaging)
- - not all cameras have tall enough film rails to accept the most 
sturdy quality (0.4mm thick #87C)

- - only #87C (0.4mm), #87, #12 and #29 (all 0.1mm) are available in
polyester, other colors only exist in gelatine (more sensitive to
moisture, scratches and fingerprints, and cannot be cleaned, in all
aspects unlike polyester)[*]

Practical: I have one (#87C/0.4mm) permanently mounted in one of my
EOS-1's, for nearly 2 years now. Still as good as day one. 

As for the filter color itself: the #25 doesn't give me the unwordly
effects I want/like....but that's a personal choice, also depending
on subject I guess (portrait/nude vs landscape/architecture).

Last winter I even sacrificed another EOS-1 for EIR with a
permanently mounted #12....the swapping of various lenses over 3
bodies (HIE, EIR, normal color) is as foolproof as can be....totally
impossible to forget a filter, or use the wrong one (don't laugh, has
happened to me several times in the past, these hostile environments
don't allow much time for thinking).


[*] note that even though Kodak/Wratten doesn't make all
intermediate colors any more (only #70, #87 and #87C I believe), I
can still supply any possible color in gelatine (different
manufacturer)

All qualities polyester (12/29/87/87C) are US$0.50 pro square
centimeter, same thing for all gelatine colors. Send me private
email for details on ordering. 


- --                 
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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