More on UV photography

[Rolland Elliott <rolland_elliott@xxxxxxxxx>]

> More on UV photography:

> "Are you sure that your current lenses are not usable for
> near-UV use, just below 400nm? I believe I have seen more than one
> reference claiming that it is far-UV (closer to 300nm) which causes
> big problems with non-UV corrected and multicoated lenses."

 No, I'm not sure.  In fact I haven't even tested them yet, but the two
 or three web pages that I've read on UV photography warn against using
 modern multicoated optics for UV work.

> "Third, M39 is by far the most universal mount on this
> planet.... 'but':you most likely loose infinity focusing with all
> (35mm!) photo lenses, as
> well as with all non-tele enlarger lenses (less than 75mm or so is my
> rough guess)....but for macro use this is all you need.
> So, this leads to the famous 'last but not least' question for
> non-bellows use: what focal length are we talking about
> here?....what is the focal range of these EL lenses?"

Nikkor EL lenses range from 40mm f/4 to a 360mm f/5.6 lens, quite a
wide variety.  I tried hand holding a 50mm f/2.8 lens infront of the
lens mount last night and discovered that I could get sharp focus on
 objects about 2.75 meters away, but no infinity focus. I just bought a
 75mm f/4 and a 135mm f/5.6 lens on ebay for a pretty good price, but
 have yet to use them.

> "[if you still don't believe in coincidence: last sunday I found a
> Kodak 18a filter on a second hand photo market....;-))....never ever
> seen one before in all the years that I have visited second hand
> photo shows....and in this case I was triggered by seeing Guenter
> Wagner's book about IR-photography, after which an old 52mm B+W
> infrared #89B was digged up (chrome, and no type indication on the
> mount)....and my 'do you have any more exotic stuff with you?' was
> met with this 18a filter....I already had two homebrew Scott UG1/UG3
> filters, but this Kodak 75x75mm also allows flash use....cool....]"

 You must be one lucky guy!  Those 18A filters cost a mint.  What
 exactly is a homebrew Scott UG1/UG3 filter?
 While your working on your UV web page chapter you'll probably want to
 note the following facts:
 1) Tiffen makes an 18 A filter
 2) B+W no longer makes its 484 filter, which I believe  is equivalent
to a 18A. 
They do however still make a 403 filter which lets in UV and some
visible violet light, but not much.

Peace Rolland Elliott





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