Collapsible Tessars for Contax

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Michael
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I'm cleaning up a 50mm 3.5 Tessar for Contax, an old nickel and black one. (see 'just arrived' post in the Contax forum). The lens unit seems to screw out of the mount almost too easily.

There is evidence that there was once a screw that came in from the back of the lens directly into the threads of mount and unit, thereby locking them together. Literally running through the threads and jamming them.

Is this original? It seems a mechanically 'dirty' way of going about the task.

Michael
 
That is original on the Contax mount collapsible lenses. "It Works". The optics modules just screw into place, up against shims. Final step is to use the set screw. The Wartime Zeiss LTM lenses do not have this set screw, and run the risk of unscrewing from the mount when you tale off a filter or hood. Jupiter-3 and -8 in LTM are the same way- can unscrew. The post-war West German Zeiss lenses use a guide pin and retaining ring to hold the optics in place.
 
Thanks, I was worried that it was someone's 'fix'. I really like the 3.5 Tessar which sort of seems better than the 2.8. Maybe it is just the condition of my examples.

Quite whether these older Tessars are any better than contemporary Elmars is, I am sure a subject that has been debated for nearly 80 years...

Michael
 
Mine is the original 5cm f2.8 Tessar, Black namering. "It was a Dog" wide-open, better at F4. Zeiss recomputed the 5cm f2.8 early on, the chrome namering version is reputed to be better. The F3.5 was superior wide-open, but the F2.8 version matches it when stopped down to a similar aperture.

The F2.8 generally goes for less money.
 
I've put the lens back together now, tidy and clean using the original shims.

Next the camera. This one's shutter fires healthily on all speeds (no slow speeds), tapes look fair, but it doesn't always 'pick up' when winding on...

I haven't gone in there yet, but it shouldn't be too difficult to work out. We'll see, but any advice much appreciated.

Michael
 
Mine is the original 5cm f2.8 Tessar, Black namering. "It was a Dog" wide-open, better at F4. Zeiss recomputed the 5cm f2.8 early on, the chrome namering version is reputed to be better. The F3.5 was superior wide-open, but the F2.8 version matches it when stopped down to a similar aperture.

The F2.8 generally goes for less money.

Mine is the 5cm 2.8 Tessar as well. Black and nickel 1371XXX. A lot less contrasty than the Sonnar obviously, but still I think it's a good lens. I assume mine is pre-recomputing too.

Jim
 
That's the original formula lens. At F2.8, it is soft compared to the Sonnar and F3.5. but at F4- much better.
 
I am waiting in the mail for a clean looking Tessar chrome 5cm/2.8. I used to own such a lens, and I like the way images can be rendered with it.
If it is dirty, then I will send it for cleaning.
 
Mine is the 5cm 2.8 Tessar as well. Black and nickel 1371XXX. A lot less contrasty than the Sonnar obviously, but still I think it's a good lens. I assume mine is pre-recomputing too.

Jim

Mine is a little bit dirty but not too bad. These shots were all taken wide open at f2.8.

6313468297_72ac1b4a3b_b.jpg


6313467663_7f716c2e94_b.jpg


6313468017_6cfb11f750_b.jpg
 
Yes, you were right! It WAS a dog.

I actually got mine on an ebay Contax III, where it sure didn't belong. I'm happy to have it too. Renders very differently from any other lens I've tried.
 
Yours should be the recomputed lens- look forward to seeing some pictures with it.

I just rebuilt a 1934 5cm F1.5 Sonnar, black trim- slightly different construction from the later lenses. It is the version that takes screw in filters. But- the rear trilpet is slightly different shape from the later lenses.
 
Thanks, Brian.

Its number is 19991xx,and it looks "like new".
I sold a lens like it, and I had nothing left that renders images like the old Tessar.
Now, I can again use such a lens for portraits at soft window light. This is where it does well.
As you know, I also have a Tessar 5cm 2.8 in LTM (adapted from SLR lens mount).
Is the old Contax lens very different optically from the SLR lens?
I see less flare.
 
Martin Thai wrote online:

"The performance of 50/2.8 Tessar can be better than 50mm/3.5 Tessar. For example, looking at the ray intercept plot of Tessar USP2724992 f2.8 Tessar, its performance is better than TESSAR USP2084714 F3.5 lens; the former has less 34d order and 5th order abberations

The key difference is that the f2.8 used higher index glasses, three of the four glasses have n >1.60, one of the positive element of cemented doublet used high refraction index lanthanium glass, n=1.717, while the f3.5 tessar used two glasses with n<1.58."

From Vade Mecum:
"The switch to chrome finish begins at about 1.89 million. 1937 1,930,150-2,219,775 289,625 1938 2,267,991-2,527,984 259,993 1939 2,527,999-2,651,211 123,212 1940 2,652,000-c2,678,000 26,000 1941 2,678,326-2,790,346 112,020 1942 2,800,000- ? 1946 2.8m * "

So my lens seems to have been made in 1937.
 
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The Sonnar 5cm F1.5 dropped the black trim at about SN175xxxx. I have seen lenses on Ebay in that range with the black trim on the mount, my SN175 block lens does not have it. Makes sense that the black trim was dropped at about the time the formula changed on the F2.8 lens.
 
Good guess- Thiele's book shows a batch of 1000 5cm/2.8 Tessars in Contax mount with your serial number range with completion date of Nov 26, 1936.

Hello Mark,
I will go with your number then. Thiele's book may be the one to trust. I marvel at the craftmanship and condition of an item that was made so many years ago. My lens has its "birthday" in twenty days!
 
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