Archived posting to the Leica Users Group, 2000/05/26
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At 6:37 AM -0400 5/26/00, Dan Cardish wrote:
>Have you found this from experience, or is this just an assumption based on
>the "APO" designation? I'm asking this because the wording used in the
>English Leica Cataloge used to describe the 90 AA isn't the same as that
>used to describe all of the R-series APO lenses, ("apochromatic corection
>for extended spectral range" for the R lenses).
>
>Dan C.
>
>At 10:38 PM 25-05-00 -0700, Henning J. Wulff wrote:
>[snip]
>>
>>Also, for IR
>>use, the new 90 does not have to be refocussed. This makes IR shooting with
>>a 90 a true pleasure.
Experience with HIE, which has the greatest sensitivity into the IR region
of any readily available film. It should be noted though that since HIE is
a very coarse film, slight optical deficiencies will not be as noticeable
as with a finer grained film. In any case, the 90 A-A makes IR photography
a great deal easier.
* Henning J. Wulff
/|\ Wulff Photography & Design
/###\ mailto:henningw@archiphoto.com
|[ ]| http://www.archiphoto.com