At 00:15 8/21/00 , Vaughan wrote:
>The challenge there is that normal optical glass absorbs UV, the
>coatings are not the main problem. Nikon and Hasselblat's UV lens are
>made from special glass that is UV transparent.
>
>
>Vaughan
Yes, it is not the coatings, it's the glass that's very absorptive. Zooms
don't cut it because of it, and if you must use glass, then the older
lenses with fewer and thinner elements work best as far as glass goes.
The Nikon and Hasselblad lenses are quartz which is transparent to the
higher UV, and that's why they are so costly. BTW, you have to shift the
focus just as with IR, but in the other direction. If you're up to
attempting a home-brew lens, Edmund Scientific sells quartz elements for
use with high UV.
-- John
-- John
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