Re: hoya R72 Filter

[Chris Hulme <chris.h@xxxxxxxxxxxx>]

In message <199608202340.AAA24091@xxxxxxxxxx>
        Willem-Jan Markerink <w.j.markerink@xxxxx> writes: 

> On 20 Aug 96 at 19:12, Chris Hulme wrote:


> > Could someone please tell me what the equivalent Wratten number is 
> > for the visually opaque hoya R72 filter?


> The Hoya R72 is definately *not* visually opaque. 
> It equals a Wratten #89B. Even the much darker 88A can be looked 
> through with some effort.
> This 89B color is also known as Schott RG695, which is used as normal 
> IR filter for both Heliopan, B+W (092) and Rollei.


Thanks for the info, Willem-Jan.  By describing it as 'visually 
opaque', I was of course referring to the fact that you can't see 
through it to compose/focus when attached to the camera.  It has 
often been described like this in UK publications which as you point 
out, is not technically accurate.

Perhaps I should stick to describing it from my comments when I 
bought this filter and looked through it for the first time, "How the 
bloody 'ell am I going to take photos through this black thing!?"  :)) 



-- 
Chris Hulme <<chris.h@xxxxxxxxxxxx>>
Stoke-on-Trent, England.


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End of INFRARED-PHOTOGRAPHY Digest 40
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