Re: Focus corrected IR-filter (was: Another New Subscriber

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

On  8 Dec 96 at 1:57, Steve Midgley wrote:

>     My equipment ranges from 35mm to 8x10 but my favorite camera for
> infrared is the twin lens Rollei - I can use the Rollei infrared filter
> (which is focus corrected for IR) and still be able to see to compose and
> focus. 

I once bought such a Rollei focus-corrected filter, but I be damned 
if I can see any effect other than color (color equals a Wratten #89B, 
see the IR-filter list on my homepage).
All tricks and methods to prove it is concave or convex in whatever 
direction were in vain. And I do have the Rollei manual/instructions 
that once again confirm the focus claim.
Yet Rollei Germany is also baffled when I ask them about it, they say 
such a focus corrected filter never existed....
It *can* be made they said, but would be quite expensive.
Would love to get more info on this!



--
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. 7