Hi Piers and all,
From: "Piers Hemy" <piers@xxxxxxxx>
>But if you insist on pointing optical equipment at the sun, I can recommend
>the products of Thousand Oaks Optical
>
><http://preview.tinyurl.com/2y7cj>
I contacted them for the solar eclipse of 1999, but they wouldn't provide
the filter in time, so I made my own homebrewed filters -- a roll of
120-format Ilford Pan-F strongly developed in an open tank. The 120 film did
not cover completely the Tamron 500mm, but with the help of a mask
everything went well.
I eventually made two different versions: one lighter (ND 4.0) for picture
taking (later used with the Zuiko 300/4.5 and other lenses) and a stronger
one (ND 6.5 approx.) for direct, safe observation -- I keep one of these in
my wallet, just in case.
Other films may have a frosted base, and thus not suitable. And colour film
(or chromogenic B&W) is strctly forbidden -- it won't block IR!
A few pics of the filters in use:
<http://cjss.sytes.net/etc/IMG_0157.JPG>
<http://cjss.sytes.net/etc/IMG_0158.JPG>
And some pics _thru_ the filters:
<http://cjss.sytes.net/etc/transito/> (The transit of Venus in front of the
Sun -- excuse the extremely dirty sensor...)
It seems to impair sharpness, though :-(
Cheers,
--
Carlos J. Santisteban Salinas
IES Turaniana (Roquetas de Mar, Almeria)
<http://cjss.sytes.net/>
--
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