Hi, Chuck and all.
>Here's a thought for an adapter with an optical element. Has anyone
>considered a focal reducer? I've never seen one for a camera lens. All
>we get are tele-extenders. But owners of Schmidt-Cassegrain telescopes
>from Celestron and Meade should be familiar with them.
[snip]
>OK, where's the catch?
The typical adapter with optical element is, in fact, a mild teleconverter
(x1.2 or so), thus allowing a somewhat longer flange-to-film distance.
But a 'focal reducer' does *reduce* the flange-to-film distance too, so
they are *not* suitable for cameras. As someone pointed out,
Schmidt-Cassegrain telescopes have a lot of back focus, so this is not
likely to be a problem.
For instance, I have never seen a focal reducer for a Newtonian 'scope
(much shorter back focus).
Best regards,
...
Carlos J. Santisteban
<cjss@xxxxxxxxxxxxx>
<http://cjss.galeon.com>
< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
|