Re: Exposure (was: Rangefinder etc)

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

On 19 Jul 96 at 2:06, Vaughan Bromfield wrote:

> To be honest I have always use Hoya filters and have never bothered
> learning the Wratten designations. So I know what a R25, K2 and O(G) filter
> is as well as 81a, 82a, but 87x I dunno.

The current listed range from light to dark is:
25
29
70
88A (lighter 88 listed in an old Wratten book)
89B (lighter 89 & 89A listed in an old Wratten book)
87
87C
87B
87A

Note that the none/A/B/C rating is not consequently used....anyone an 
idea why? Did they just pick numbers and letters as seem fit?

 
> I have the Hoya opaque IR filters, and my understanding is that they are
> still readily available. The actual designations I cannot remember,
> something like IR650 or similar designating the visible-light cut-off point
> -- one cuts-off deeper (ie transmits less far-red light) than the other. I
> have the "shallower" one, and if you hold it to a light you can see a deep
> dark red image through it, so I guess it has similar transmission
> characteristics to a bottle of Port!

I am still surprised that people call R72 opaque. I find it a very 
usable filter to look through, even when mounted on a SLR.
Of course, you need bright sunlight, but IR is not much fun without 
anyway.
 
> So perhaps much time and effort may be saved looking into the Hoya range of
> filters. Unless, of course, the *challenge* of diy IR filters is your thing
> ;-)

Well, I personally prefer the slide-in system of Cokin, especially
with opaque filters and SLR's. The on and off mounting with screw
filters, when switching between composition and actual exposure is
murder on the screw thread of both filter and lens. Taking pic's
with my Horizon (viewfinder) pan camera is a breeze in that respect.

PS: can someone do a check on the availability of the Hoya R90?

BTW: I just got off the phone with Kodak Holland: no information on 
the E6 Ektachrome IR, although he did knew about plans & rumours. He 
believed that the PhotoKina would be the place and time for such 
news. Not with this list around....;-))
I also asked him about Kodak IR gel's: only 87C is currently 
available....albeit I recall another one on special order. Can anyone 
do a check on the US situation? Is only Europe deprived of this 
stuff?



--
Bye,

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The difference 
between men and boys
is the price of their toys

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