Alingment, lenses and other...

[Ed Sukach]

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (tschmid @ May 7 2003, 12:30 PM)</td></tr><tr><td id='QUOTE'> A Zeiss S-Tessar from the 60&#39;s (a "low-end" el-lens from Zeiss that still outperforms some modern ones), e.g., passes UV light seamless and can still be focused sufficiently exact with visible light.</td></tr></table><span class='postcolor'>
Hmm... interesting. What material is used for the elements of this lens?

[Thilo Schmid]

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Ed Sukach @ May 8 2003, 01:14 AM)</td></tr><tr><td id='QUOTE'>Hmm... interesting.&nbsp; What material is used for the elements of this lens?</td></tr></table><span class='postcolor'>
Ed,
I don&#39;t know many specs of that lens. It most probably has normal optical glass. From the name, I would derive that it is a four-element design (which absorbs less UV than a six- or seven element). However, the lens has a strange coating. The MC coatings of Zeiss lenses from a current Apo-Sonnar to 60&#39;s Luminar usually have all the same look. This one looks like being neither single nor multi-coated. It has a yellow-brownish reflection.
I have to be more precise about the term "passes UV light seamless". I have not performed any scientific measurements on that and "UV-light" is a flexible term. I have done some experiments with a 390nm bandpass filter and it worked well. The lens might not pass 300nm. I don&#39;t know.

[Aggie]

..

[Ed Sukach]

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (tschmid @ May 8 2003, 12:00 AM)</td></tr><tr><td id='QUOTE'> I have done some experiments with a 390nm bandpass filter and it worked well. </td></tr></table><span class='postcolor'>
Any idea of the amount of attenuation at 390nm?

[Donald Miller]

If this lens does indeed pass 390 nm UV without a large degree of attenuation, then one would be advised to pick them up as an investment. I spoke with Michael Smith the other evening and he has informed me that the developer of the light source for enlarging on Azo has largely finished the development phase. This is a totally new lamp which a manufacturer has developed entirely for this application. So the lens that you have described and it&#39;s ability to pass 390 nm UV makes it attractive. 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.

[Robert]

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Aggie @ May 8 2003, 02:11 PM)</td></tr><tr><td id='QUOTE'>
Now how would the enloarging lenses hold up as a lens on a camera? </td></tr></table><span class='postcolor'>
Some people use enlarger lenses for close up work. You need less bellows with something like a 80mm enlarger lens. The bellows factor can slow things down enough that exposure are long enough to not need a shutter. Or I guess in a studio a person could use flash.

Then you have the old way of using your camera lens on your enlarger.

[Thilo Schmid]

</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Ed Sukach @ May 8 2003, 08:54 PM)</td></tr><tr><td id='QUOTE'>Any idea of the amount of attenuation at 390nm?</td></tr></table><span class='postcolor'>
Ed,
I cannot provide absolute values, but this lens was more than 2 f-stops faster on OWRO FB (a discontinued classic silver-rich emulsion FB) at 390nm than a normal 6-element Rodagon. The light source was a “normal” 300W el-bulb. I have no information on the spectral sensitivity of ORWO FB.

[Thilo Schmid]

</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.

[Donald Miller]

Thanks, I will keep that in mind.

[fingel]

Hey Aggie,
I&#39;ll tell you a little bit more about that shutter. It is a LUC shutter, kind of like a packard shutter, but round and uses a standard cable release. It is dial set like the old compur shutters and has 3 settings. Bulb, a shutter speed of about 1/15 sec, and open-for focusing. It fits on the outside of a lens with a diameter of between about 40mm and 52mm by 3 adjustable set screws. I use it on what I think was originally and enlarger lens. It is a 135mm Hermagis Anastigmat Hellor. It is uncoated, has some bubbles in the glass, and has a slight haze. Not what I would want to use for enlarging, but is great for portraits. I haven&#39;t shot anything with a modern enlarging lens, but am planning to soon.