Very Early Coated Lenses- the first 10 years from 1935 to 1945.

I have a Biogon 239xxxx and a Sonnar 5cm F1.5 255xxxx that have the red T. The Sonnar aperture ring goes to F11, and construction is similar to the uncoated lenses. Zeiss produced coated and uncoated lenses in the same batch. By the 267xxxx batch of Sonnars, most were coated and the 5cm F1.5 stopped down to F22.
 
lukx said:
Yes, the low serial number in combination with the T seems very early. The technology was there in 1937, undoubtedly. The T looks very straight and precisely machined, I have no indication of it being a fake, other than the fact that it's very early. I may ask Chris Andreyo of Skyllaney what his verdict is, though he is generally not too concerned about fakes.
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Chris is currently working on his own version of the 2/50 Sonnar which ought to be very interesting and may account for his indifference to counterfeits. He used several samples of early coated CZJ lenses, circa 1937, as the basis for the revived lens.
 
Chris has reverse-engineered many oddball Sonnars, most are not fakes.

I will be getting one of the first 10 Bertele Sonnars, SN9. I went with the Beatles for choice of serial number. I will test it alongside of my 1934 5cm F2 Sonnar, that I converted to LTM. Perfect Glass. I also have an early 5cm f2 Sonnar T converted to LTM.

As far as the Red T on a 201xxxx Sonnar, it is most likely original. I'd start using my cool new trademark at SN 2M.
 
Räuber said:
I read that it was possible to add the coating for money to uncoated Sonnar lenses. So Zeiss was not as quit about it as it seems. There have to be coated lenses without the red T too.

I'm sceptical about the Nr. 2016056 in this thread. I saw the auction for this lens and it is a little strange. It is the earliest Sonnar lens with a red T mark I have seen so far. It dates to 1937 and the next Sonnars with red T mark I know of are from 1939. There is this huge gap... Maybe the TO can sheet some light on this as he has seen more Sonnar lenses as we all together. :-D Did Zeiss add coatings AND put a red T on the name ring on previously sold uncoated lenses? This would be the only legit explanation for the red T on Nr. 2016056. Otherwise someone might have created a fake name ring or T mark.
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Well, yes and no. We are talking about pre-war to wartime and I don't think anyone other than the German Govt. could get their hands on a coated CZ lens then but during wars with shortages of this and that I don't doubt for one moment that some went astray in a bit of horse trading and - for a whale after the war - there was a cottage industry and an official one coating lenses.

I have a large collection of 1930's and 40's camera magazines and have seen nothing like a review or advert for any coated lenses.

Regards, David
 
I've a 1937 Summar in the heap somewhere and would love to know if it was one of the experimental ones or coated post 1945/46.

Regards, David
 
Sonnar Brian said:
Chris has reverse-engineered many oddball Sonnars, most are not fakes.

I will be getting one of the first 10 Bertele Sonnars, SN9. I went with the Beatles for choice of serial number. I will test it alongside of my 1934 5cm F2 Sonnar, that I converted to LTM. Perfect Glass. I also have an early 5cm f2 Sonnar T converted to LTM.
.
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That’s exciting! When is the Bertele supposed to be released to the rest of us?
 
f.hayek said:
That’s exciting! When is the Bertele supposed to be released to the rest of us?
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The latter- I don't have a date. It is getting soon. The last 2 years have been difficult getting things manufactured. I will say that Chris used this time to come up with a highly refined design, the focus mount should be amazing.

I am really excited about this lens, and will be putting it through the paces. I'll be reporting on it here at RFF. I'm also getting a post-war Zeiss Opton 50/1.5 converted to M-Mount using the new Omnar mount. Excited about that as well. The post-war Sonnars do not fit into a Jupiter mount.
 
Sonnar Brian said:
The vacuum deposition equipment was installed in 1935. I have a 175xxxx Sonnar with coated front element, and have worked on a second one from the same batch. The 1909xxx Sonnar is hard-coated on all surfaces. It was like wax paper when received, and the retaining rings were all unmarked- no spanner marks. No red T.

The Black rim filter ring started in the 272xxxx batch. I have a couple from that batch, 27250xx silver and 2726xxx is black.
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As I said the black filter rim is uncommon for CRF Sonnar 5cm F1.5 from those last war years. But it is common on most (fake) LTM Sonnar 5cm F1.5. But the serial number is valid so it was produced in Jena.

I can only scratch my head and wonder how does the lens manufacture was working in Jena? There are little and big changes within batches. Coating is just one thing. There is no clear line or pattern which lenses are coated when they introduced coating to the lens manufacturing. But there are other features like lens mount. There are batches where you will find different mounts in one batch. And not even the Thiele serial number book managed to provide a clear image what kind of lens was produced in a single batch. There seem to be exceptions whenever body details and features where changed. You can find single lenses that have those features before the mass get them and there are single ones that have the old housing after the design switched. You see this with prewar Carl Zeiss Jena production, you see it with East German Carl Zeiss Jena and you see it with West German Carl Zeiss (Opton).

It does not make a lot of sense. One would think that on the start of a new batch a construction plan with all details about size, materials, fonts, colors is provided by the design department. And then the craftsmen will build the lenses according to this plan until the batch is finished. But I have the impression that they changed the plan for all working lines at once. And they changed them a lot especially in the last WWII years. Maybe they tried to change the body design to save some material like metal. Maybe they tried to make the production more efficient by simplifying steps in the workflow. I suspect that there where multiple production lines with different work speed and maybe own serial blocks. That way when the construction changes it affected different parts of an ongoing batch. A pretty confusing approach. This leads us to batch 69 from December 1945 with 5000 lenses that is a mess of CRF and M39 Sonnar 5cm 1.5 with black and silver filter rim that is followed by batch 68 in January 1946. I can not see a clear pattern here.
 
Blocks of Serial Numbers were reserved for batches, and looking at Thiele- you can see that the batches overlapped in production dates. Parts were produced in batches, and probably revisions were made. The revisions were not so great that it prevented the parts from being used. The Black Rim lenses are common in SN block 285xxxx. They are not common in the 272xxxx batch, but are there.

The Zeiss lenses finished at the end of the war and early post-war era are not fakes, but not regular production. I've worked on several- including one with the middle triplet "Hot Mounted" into the barrel. Let the barrel center the elements, and cement cure. The middle triplet could not be removed. The lens was a good performer, and both surfaces cleaned up nicely.

I've seen set screws used to hold the fixture for the rear triplet into the barrel and a set screw under the aperture ring used to hold the namering in place on the wartime lenses. Most of the wartime lenses I've taken apart have the set screw for the rear fixture. Some have it for the namering. The fact that the presence of the set screws in some but not others - means that a standardized assembly procedure was out the window during the war. I learned the hard way to assume the set screws are there, and remove the aperture ring to look for one before taking off the namering. This is true for the 5cm F1.5 Sonnar made after SN 267xxxx.
 
I too have somewhere read that Zeiss offered to coat older lenses after the war and that they also engraved the red T then. That explains some of the very early coated lenses with the red T. But others offered the same service after the war. An 18 cm Sonnar once offered on Ebay came with a receipt from 1952 for the "original Heraeus coating" it had received. Heraeus was a company that cooperated with Zeiss in the development of the vacuum chambers for the coating process. I too have an 18 cm Sonner that has been coated after the war by somebody, it has no red T. The rear lens is permanently fixed in its mount, so the mount was coated too!
I haven't seen any mention of the partly coated lenses. Here for once we have some contemporary information. In an article published by Zeiss-Ikon in august 1941 we can read (my translation):
"For the time being the two outer surfaces are not being coated. Although the durability of the coating layer isn't that poor, you can carefully clean the surface with a soft brush, we have to take into account that lenses in the hands of non-professionals won't be treated with the proper care. That is why the two outer surfaces are left untreated". Later, already during the war, they found that by "baking" the lenses at high temperature they hardened the coating layer. In a footnote to the article the author informs that "at the moment" the only coated lens available from Zeiss-Ikon is 1,5/5cm Sonnar. Here are the 1,5 Sonnars I have examined:

June 1939 2553566 partly coated
August 1939 2610001 partly
August 1940 2675947 partly
2676058 partly
2676899 fully
March 1942 2792143 fully Arriflex
January 1943 2725231 partly
July 1943 2786838 fully

JakobN

Partly coated on the left, fully coated on the right. Below the coated metal part.

P1040924.jpg P1040948.jpg
 
I have tried to find out whether Zeiss produced coated and uncoated lenses in the same batch. I picked the Sonnar 2/5cm because of the easily spotted wartime version with its "hovering" aperture ring.
I noted the number of every lens I saw and whether it had the redT or not. The result so far:
30 numbers from 2586622 to 2684286 all uncoated except one.
79 numbers from 2684335 to 2710123 all coated except one.
Zeiss clearly began coating the Sonnar 2/cm at a later date than the 1,5, and by then they apparently had the capacity to coat all the lenses.
In an article from 2016 on Zeiss.de there is more information. In 1938 Zeiss had 17 vacuum chambers working exclusively for the military, but before the end of the war they had over 100.
Coated Biotars and Sonnars were presented at the Leipzig Spring Fair in 1940. In 1941 pr. month about 300 Sonnars 1,5 in Contax mount were being coated.

JakobN

PS: In my former post I forgot to mention that all the lenses have the redT. P1040940.jpg
 
In an article from 2016 on Zeiss.de there is more information. In 1938 Zeiss had 17 vacuum chambers working exclusively for the military, but before the end of the war they had over 100.
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It does beg the question as to what the military was supposed to be doing with all these coated lenses...

Apart from camera lenses, which would have surely been a very small % of production I guess there would have been sights, rangefinders, binoculars, scientific instruments etc...and then 'the military' would have been the only customer and even when their forecasts were obviously optimistic when they said jump, you jumped.
 
JakobN said:
I too have somewhere read that Zeiss offered to coat older lenses after the war and that they also engraved the red T then. That explains some of the very early coated lenses with the red T. But others offered the same service after the war.
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Thank you JacobN for the background information. Now that makes sense. So the very early T marked Sonnar might have a Zeiss-Opton T coating.

My impression is that the Zeiss-Opton / Carl Zeiss T coating is more effective than the previous and East German Carl Zeiss Jena T coating. The Opton Sonnar lenses are very contrasty. My impression is that the after WWII changed lens design of the Zeiss-Opton Sonnar 50mm F1.5 is not any better than the previous WWII Sonnar 5cm F1.5 lens design. They are equally as sharp and there is no real improvement from the older to the new design I can spot. The increased contrast and improved clarity seen with Zeiss-Opton Sonnar lenses seems to be a result of the new T coating. When comparing the older lens with the new lens I find them not just equally as sharp but sometimes small image details even look better with the older design. But we talk about a 1% difference here. You can't go wrong with any Sonnar 5cm / 50mm F1.5 from 1935 and later (maybe with one big exception but it is too early for final judgement). Since I could not use earlier Sonnars I can not say how those (none coated) Sonnar lenses behave.

Today it is easy to get coated glasses (from Zeiss too) and I wonder if one could easily add coating to those old lenses. How much of an improvement could be expected?
 
I have coated and uncoated 5cm F1.5 Sonnars made very close together. The uncoated lens has a beautiful Bloom to it, acts as a natural lens coating. Not as even across the surface as the coated lens, but very effective. Remember the concept of coating a lens was to duplicate the effect of bloom. It was noticed that older lenses with a Bloom transmitted more light than new lenses. After 80 years, the uncoated optics acquire a natural coating.
 
Dralowid said:
It does beg the question as to what the military was supposed to be doing with all these coated lenses...

Apart from camera lenses, which would have surely been a very small % of production I guess there would have been sights, rangefinders, binoculars, scientific instruments etc...and then 'the military' would have been the only customer and even when their forecasts were obviously optimistic when they said jump, you jumped.
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They had to have the best, of course..

There's a lot of photo's on the www showing the military using them and I read an article in a wartime magazine about a Leica IV that a captured bomber crew had with them. The "IV" was a IIIa from memory or a IIIc. Probably the letter as it would be unlike early ones seen in GB. Also seen on the WWW and article about photo's from cameras liberated from bomber crews.

Apologies for not being able to lay my hands on them at the moment.

Regards, David
 
Sonnar Brian said:
I have coated and uncoated 5cm F1.5 Sonnars made very close together. The uncoated lens has a beautiful Bloom to it, acts as a natural lens coating. Not as even across the surface as the coated lens, but very effective. Remember the concept of coating a lens was to duplicate the effect of bloom. It was noticed that older lenses with a Bloom transmitted more light than new lenses. After 80 years, the uncoated optics acquire a natural coating.
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Your telling us that 80 years of accrued muck becomes a coating?? Seems more like haze than coating. You don’t clean these lenses?
 
james.liam said:
Your telling us that the everyday muck becomes a coating?? Seems more like haze than coating. You don’t clean these lenses?
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Haze is different from Bloom.

Haze is typically from outgassing lubricants or moisture that has dried and covered the surface of the lens.

Bloom is an oxidation of the glass that changes the refractive index. This is where the idea for coating optical surfaces came from.
 
David Hughes said:
They had to have the best, of course..

There's a lot of photo's on the www showing the military using them and I read an article in a wartime magazine about a Leica IV that a captured bomber crew had with them. The "IV" was a IIIa from memory or a IIIc. Probably the letter as it would be unlike early ones seen in GB. Also seen on the WWW and article about photo's from cameras liberated from bomber crews.

Apologies for not being able to lay my hands on them at the moment.

Regards, David
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The Leica IV had a combined VF/RF, wider base.
The FED 2 looks more like a Leica IV than the IV looks like a IIIa.

https://gmpphoto.blogspot.com/2013/02/leicas-that-never-reached-market.html
 
Neblette uses the term "Bloom" and Kingslake uses "Tarnish", both describing H Dennis Taylor in 1896 noting that old lenses transmit more light than new ones of the same design. The increase in transmission is due to the refractive index of the glass being different at the surface layer. Interaction of the glass and the environment.

Tarnish is described as discoloring due to oxidation. Over enough time, exposure to air tarnishes the glass.
 
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