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Re: Newbie


  • From: Helmut Faugel TE <htf@xxxxxxxxxx>
  • Subject: Re: Newbie
  • Date: Thu, 19 Apr 2001 15:56:47 +0200 (MET DST)

On Thu, 19 Apr 2001, Andreas wrote:
> Thank you all for your comments.
> 
> To Helmut:
> 
> It is a EOS. Are you saying that my "modern" 50mm lens system is useless
> for UV?

Not useless but they can absorb a large amout of UV. 

BTW: The 'standard lens' my friend measured was a Carl Zeiss CB 80/2.8
for Hasselblad. I should have known this, because he used to shot a bit
larger formats, 13x18cm etc.

> If so, then I'd go through with trying to remove the coatings
> before buying a new or rather an old lens system.
  
I have absolutly no idea how lens coatings can be removed, and I
would not do it on a lens having 10 or more air/glass surfaces.

But old uncoated Tessars with six air/glass surfaces are giving
good results using slide film.

> bhphoto.com have an assortment of B&W Black Glass Lenses, some really
> cheap (~35$ for a 52mm). It says that 
> 
> "Although this dark violet filter transmits a small amount of visible
> light, it completely blocks wavelengths longer than 360nm."

Yes that's right, B+W has also the transmision curve of this filter
on their website. But I think using normal b/W film should not result
in recording this small visable amout of light because this transmission
start beyond 650nm AFAIK and normal b/w is blind to this wavelenght.

> which is conflicting information, as I see it, since the upper limit for
> our vision is usually given as 400nm.

Do not take the limits of vision to serios, there are no "hard" limits.

People do see laser flashes at 353nm as well as at 1063nm. It is only
a matter of intensity.
 
> I'd like to know if anyone has experience with the B&W filter.

I have no personal experience, but Guenter Spitzing the author
of "Grenzbereiche der Fotografie" and "Moderne IR- und UV-Foto-
grafie" has used this filter with sucess. Go to the next library
and look for these two book.


regards

Helmut
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