</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (dnmilikan @ May 8 2003, 09:32 PM)</td></tr><tr><td id='QUOTE'>What focal lengths was this offered in? I would be looking for a 150 mm if my el nikkor does not provide the necessary band path.</td></tr></table><span class='postcolor'>
The S-Tessar I am speaking of is a long discontinued lens from the 60&#39;s (guessed by its serial no.). I do not know in which focal lengths it had been manufactured. Mine is a 75mm that covers 6x6 and has an excellent overall performance when stopped down to at least f8. It was most likely an OEM-lens for a 60&#39;s repro camera.

I would recommend to buy old uncoated or single coated 4-element lenses for that purpose (e.g. Rodenstock Ysaron). They are usually cheap and will transmit UV light better than modern six-element versions. The only problem is, that most of these lenses will suffer from chromatic aberrations and will have a different focus point for visible and UV light. However, most modern lenses (even APO lenses) will have exactly the same problem. On the other hand will shorter wavelengths deliver better resolution. So you may not suffer that much from smaller apertures and extended DOF.