Re: Newbie

[Helmut Faugel TE <htf@xxxxxxxxxx>]

On Wed, 18 Apr 2001, Andreas wrote:
> My setup is a Canon 50mm with a Cokin P filter holder. Unfortunately
> I do not yet have a UV-transmitting Filter (the difficulty in getting
> a Kodak Wratten #18a combined with the arrogance of the local sellers
> has already delayed this project for several months).
>
> Therefore I would very much appreciate any suggestions on how to get
> a suitable Filter sent to Vienna. My best bet at the moment is a
> Hoya 360 (53mm diameter or square) sent from the US (no idea how long it
> would take) for ~100$. Unfortunately I have no clear picture of how
> the filter would look like, but since I am beyond caring now, I'd
> probably
> glue it to my Filter Holder or somesuch (I do not plan to use this
> system for anything else).

I would try to contact either Heliopan(http://www.heliopan.de/ ) or 
B+W Filter(http://www.schneiderkreuznach.com/produkte.htm) in Germany.
As far as I know you can order a glas filter compairable to a #18A
with a screw mount to fit onto your lens. The price should be below 
100 U$.

> Furthermore, I am not sure how much UV can penetrate through the 50mm,
> it was suggested to me that one can remove the coating of the lenses,
> which would involve opening the 50mm and removing the lenses & getting
> them back. Please tell me if you think that's feasible.

Which Canon SLR system are you using now? FD(manuell focusing) or
EOS(autofocus)? For the EOS cameras it is relativly easy to adapt
for example old M42 screw mount lenses like old 50/2.8 which are
using a Tessar like designs. The adavantage of these lenses are
that the are cheap and only using four elements in three groups
of 'old' glass with a rather low refraction index so that the
absorbtion in the glass should not be high, and the lens coating 
were only single oder double layers which also do not reflect/
absorb much UV light.

A friend of mine has measured the transmission of standard lens
(must have been some 50/1.8 from Pentacon) and has compaired it 
with an UV-Filter UV (0): 
http://members.tripod.de/selzer/Photo/uvfilter.html

Pretty much absorbtion at 360nm ...


regards

Helmut
*
****
*******
******************************************************
*  To remove yourself from this list, send:          *
*         UNSUBSCRIBE INFRARED                       *
*       to                                           *
*         MAJORDOMO@xxxxx                            *
*----------------------------------------------------*
*   For the IR-FAQ, IR-Gallery and heaps of links:   *
*  http://www.a1.nl/phomepag/markerink/mainpage.htm  *
******************************************************