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Re: Newbie (UV)




The purpose that our eyes absorb UV is probably to
protect them from it. It's quite nasty to living
tissues (even UVA) and can cause cataracts (milky lenses)
and many other unpleasant problems. UV is
used in many disinfection systems! Besides,
even if UV got through to the retina, the blue
responsive cells would be unlikely to respond to them.
I suggest that you stick to ceamera film!

Marek.

>From: Andreas <a0000613@xxxxxxxxxxxxxxxxx>
>Reply-To: infrared@xxxxx
>To: INFRARED@xxxxx
>Subject: Re: Newbie (UV)
>Date: Fri, 20 Apr 2001 11:49:16 +0200
>
>To Clive Warren
>
>"The U-V filter in the human lens has a yellow
>appearance and also absorbs heavily in the violet and blue. This
>filter is not present in the lens of cats, dogs and predators. They
>receive much of the U-V light that we filter out."
>
>This is really a big problem for me, since I'd like to extend my vision
>regions which exclusively belong to insects (and crustaceans with
>compound eyes). However, their visual receptiveness has another peak
>below 400nm, which mammals lack. That peak can be thought of as another
>color (most insects lack the "color" red), while non-primate mammals do
>not have color vision, if I remember correctly.
>
>Can you give me any references to how much UV cats et al. can see and
>actually use? I have lots of articles about insects, yet little about
>that.
>
>
>ad Setup
>
>The basic problem I have is that if I buy the filter to fit the
>lens-system, I ought to be sure the lenses actually transmit UV.
>
>The lens system I have now has few elements (though I am not sure how
>many), it is a simple non-zoom thingy. Problem is, it isn't antique.
>A technician at the biology department suggested to remove the lens
>coatings using a metal polish (Unipol). That isn't difficult, only to
>get to all the lenses, I'd have to take apart the whole thing.
>
>Since I do not intend to use the 50mm apart from doing UV, I'll go ahead
>with removing the coatings before trying to get an old lens as most of
>you suggested. I'll let you know if I can pull that one off ;-)
>
>
>The B&W 403 filter (-> Schott UG1) you suggested would work nicely, I
>hope, and the 52mm that is the correct one for me (I think so) only
>costs 36$ yet they charge 27$ more for shipment. In addition, 4-10 weeks
>until they have it...
>
>BTW has anyone experience with the Tiffen 18A? Altough I am not sure if
>one can get it outside the US.
>
>Thanks again
>Regards
>Andreas
>
>--
>
>     \  _.-'`-._     "I believe I have acted rightly in steadily
>      >< DARWIN >    following and devoting my life to science."
>     /  `-.__.-'                               - Charles Darwin
>          L  L
>*
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