In the telescope, I'm using a 420nm long pass. It has a faint yellow
cast, yet really kills the UV when I use it with the 380nm LEDs. The
420nm yellow cast is barely there. That it, it won't turn a blue sky
green like some warming filters do. I'm going to order a 415nm from
Andover for extreme long distance use. From that point, I can judge if
it turns the sky green. B&H sells the Schneider Optics 415nm as a filter
for B&W use.
I have a book on shooting from aircraft, which mentions the UV effect on
haze. However, it really didn't go into filtering. I did mention
shooting a third of a stop faster (less light) since cameras don't set
their exposure accurately when used under airborne conditions.
bkubs@comcast.net wrote:
> Singh Ray is still around: www.singh-ray.com/index.html but I don't see a UV
> filter in their catalog.
>
> Bernie
> -------------- Original message ----------------------
> From: "James L. Sims" <jlsims@knology.net>
>> Most UV filters are just glass, with IR coatings - glass will filter
>> some UV, I seem to recall less than 20%. Singh Ray did make a real UV
>> filter but it wasn't cheap and I don't know if he is still in business.
>>
>> Jim
>>
>
>
>
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