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Were wartime black Summarex lenses coated?


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24 minutes ago, derleicaman said:

Also, given the formula for arriving at the front diameter of a 1:1,5 lens, there is a significant difference and this is much harder to reconcile.

I am not sure, since obviously I cannot test it, but I presume that the diameter of a 1:1.5/9cm lens would have obstructed the rangefinder of a LTM Leica. The postwar 8.5 cm Summarex does not obstruct it without hood. Though if you add just  a little bit - which you can test with the hood on the 8.5 version - I think that the the edge opf a 1:1.5/9cm lens would have obstructed half of the rangefinder's window.  

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Now we are beginning to go down the rabbit hole! The Spanner referred to here was the Spanner IR Device used in nightfighting aircraft. The picture I have here appears to be a Dornier. A high speed lens is used in conjunction with the image intensifier for "night sight". Another device Leitz worked on for the Wehrmacht was the FG 1250, which may or may not have been used in combat on the Panther tank. Pictures of this device are in the Geburtstage Buch. I don't have my copy handy now,

I think I'll try to contact Marco Cavina : he has published those two interesting schemas, but the writings have been clearly edited by him : Hello guest! Please register or sign in to view the hidden content. Hallo Gast! Du willst die Bilder sehen? Einfach registrieren oder anmelden! In the contest of this discussion , the natural question is : in the original drawing by Berek, how was described the lens ? as a 8,5 or a 9 cm ?  the name surely wasn't decided... it's a commercial decisi

Wilson, this has always been my thought as well. Being a high profile company in the Third Reich, one would certainly have to have made the appearance of being a good corporate citizen for the regime, even if your heart was elsewhere. Also remember, that there were also members of the workforce, the rank and file, that were very much for the Reich and were willing to inform if they felt people were stepping out of line. I found it ironic, that even in wartime, that Leitz had problems supply

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2 hours ago, wizard said:

And, as you say, without further information it will be difficult or even impossible to find out which lens was referred to in that letter. It might even be the superfast 9cm f1.1 lens mentioned above by UliWer.

However, irrespective of what particular lens was referred to in the letter, we now know regarding the Summarex lens that at least one prototype version marked as 'Summar 9cm f1.5' exists, and possibly others marked as 'Summarex 9cm f1.5', whereas the regular Summarex is marked as a 8.5cm lens. To find out whether there is any difference between those lenses, and if so which differences, is a task that I find quite interesting. And in this regard I try to rely on facts, not on speculations. I may add that the perception that a lens has a focal length of 9cm just because it is marked as a 9cm lens may also be considered as speculation. And I hasten to add that no offence is intended, William. Rather, I am truly interested in resolving those questions.

Andy

Don't worry about offence, this is only a discussion about some lenses that were made about 80 years ago. 

I have heard from Jim Lager and he tells me that he agrees 100% with Lars. He has handled 541021, which is in a private collection, and  he has recorded it as a Summarex in his notes. He has a recollection from over 20 years ago that the 541021 item looked like a mock-up and was not 100% ready to deliver images. The photos of 541056 in his book are attributed to a C Bellon who may be the owner or the author of the French article. I note the comment above about the possibility that this lens has been revised or refurbished.

He quotes a reference to a 9cm f1.5 lens from Kleinbild-Foto Jahre 10 Heft 5 pages 66-67 and he says that this is dated Jan-Feb 1941.

Jim will get back if he has any shipping/delivery records for the 541XXX lenses. He feels that the prototypes for the Summarex lie within this number series. 

That is about it for now.

William

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19 minutes ago, willeica said:

Don't worry about offence, this is only a discussion about some lenses that were made about 80 years ago. 

I have heard from Jim Lager and he tells me that he agrees 100% with Lars. He has handled 541021, which is in a private collection, and  he has recorded it as a Summarex in his notes. He has a recollection from over 20 years ago that the 541021 item looked like a mock-up and was not 100% ready to deliver images. The photos of 541056 in his book are attributed to a C Bellon who may be the owner or the author of the French article. I note the comment above about the possibility that this lens has been revised or refurbished.

He quotes a reference to a 9cm f1.5 lens from Kleinbild-Foto Jahre 10 Heft 5 pages 66-67 and he says that this is dated Jan-Feb 1941.

Jim will get back if he has any shipping/delivery records for the 541XXX lenses. He feels that the prototypes for the Summarex lie within this number series. 

That is about it for now.

William

Thanks William, I talked to Jim yesterday about this. He gave me the same answer, and he thinks that unfortunately he did not photograph 541 021. I have made some inquiries with sources in Wetzlar, and they have promised to get back to me next week. Indeed, we shall see what transpires.

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1 hour ago, UliWer said:

I am not sure, since obviously I cannot test it, but I presume that the diameter of a 1:1.5/9cm lens would have obstructed the rangefinder of a LTM Leica. The postwar 8.5 cm Summarex does not obstruct it without hood. Though if you add just  a little bit - which you can test with the hood on the 8.5 version - I think that the the edge opf a 1:1.5/9cm lens would have obstructed half of the rangefinder's window.  

I was giving this some thought, and I will have to measure my black Summarex to verify the width of the lens barrel. Someone on this thread posted up what they thought was the front diameter, using the formula of dividing the focal length by the aperture. If we do this math, we end up with 56.67mm for the 8,5cm, and an even 60mm for the 9,0cm. If my memory is correct, this should be what is referred to as the "free aperture" of the lens, which does not take into account the lens barrel itself. We do know that the filter size is 58mm for the production Summarex. Given the math to determine the free aperture, this would lead me to believe there never was an actual 9,0cm 1.5 lens, but only the 8,5cm that for whatever reason was labelled as 9,0cm in the prototype phase. I would think that even without a caliper or ruler that one could clearly see the difference in diameter of these two lenses.

Edited by derleicaman
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Some more food for thought. A significant part of the wartime production for Leitz involved the design and production of the rangefinder/gunsights for the German Panzer tanks. Leitz supplied all of these from the Panzer II tank, through the Panther Mark V tank, and the Tiger I and II. Pictured here are the TZF (Turmzielfernrohr) 12 and 12a from the Panther tanks. This accounted for many tens of thousands of units, which were much more expensive capital goods when compared to cameras and microscopes.

In one of the pictures you can see the custom wooden box that the sights were shipped to the supply depot and then on to the tank factory or forward service depot. These wooden boxes were made by the Zwangarbeiter (mostly Russian women) that Leitz had working at the factory. Their barracks were located on the Lahn Insel (Lahn Island) not far from the factory. There is a football field there today. Elsie Kuhn-Leitz was involved with helping with their working conditions during the war. I have seen pictures from the old Hausertor Werk where these sights were made, with the large wooden boxes stacked up near the work tables.

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Am 9.4.2021 um 21:14 schrieb derleicaman:

Someone on this thread posted up what they thought was the front diameter, using the formula of dividing the focal length by the aperture. If we do this math, we end up with 56.67mm for the 8,5cm, and an even 60mm for the 9,0cm. ...  Given the math to determine the free aperture, this would lead me to believe there never was an actual 9,0cm 1.5 lens, but only the 8,5cm that for whatever reason was labelled as 9,0cm in the prototype phase. I would think that even without a caliper or ruler that one could clearly see the difference in diameter of these two lenses.

Bill, thank you for confirming my thoughts on this issue. This is exactly where I was heading at, namely that there likely never was an actual 9cm f1.5 lens at that point in time, for the reasons pointed out by you, me and UliWer.

Andy

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Here is some interesting information that Jim Lager passed on to me. This is a photo magazine, Kleinfilm-Foto, from Jan-Feb 1941. In it, an article talks about Leica and the development of high speed lenses. Of particular interest is the last sentence where it mentions "an outstanding lens is the 9cm, 1:1,5 lens." It does not say whether is a Summar or Summarex, only that it is a 9cm lens. The article also talks about another high speed lens from Leitz, the 7,5cm 1:0,85 Summar. Could there be a pattern here? High speed lenses with the name Summar. Remember, Leitz naming convention was based on lens speed, not lens design type as at Zeiss. Leica lens naming is still based on lens speed, i.e. f2.0 lenses are Summicrons, f1.4 lenses Summilux, etc.

These comments in the article are from Otto Zimmerman, who Jim believes was the head of the Optics Department at Leitz, Wetzlar.

In addition, Jim says there are no written entries for 541055 or 541056. He shows 541056 in his Vol.2, Leica Lenses book. The notation for 541057 says Summar 9cm shipped to Berlin on 10.5.41. 541058 shows 9cm 1:1,5 shipped 25.11.41 to Berlin.

My educated guess is that 541057 and 541058 were sample lenses marked 9cm, when in fact they were actually 8,5cm lenses. One of them, if not both of them, were marked Summar. These lenses were then shown to the powers that be at the OKH. Upon inspection and possible testing, the OKH placed the order with Leitz at some point for the lenses that were finally delivered in the batch from 593100 on in 1943.

Again, we can only be guessing that at some point, Leitz changed the engraved focal length to 8,5cm from 9cm, and the name from Summar to Summarex. One can only speculate why they were marked 9cm. It is highly unlikely that the 9cm and 8,5cm lenses are in fact two different lens designs. More likely would have been a rounding up or rounding down of the actual focal length. Hypothetically, the actual focal length could have been 8,7cm, and these were rounded up to 9cm, perhaps for marketing purposes or simplification of the lens catalog listings. For example it is well known that the actual focal length of the Rigid 50mm Summicron was actually closer to 52mm, and the lenses were marked as 50mm. We will never know unless more documentation comes out.

I would also make a strong suggestion that the lenses sent to Berlin in 1941 were not coated. It is entirely reasonable to assume that the coating that Zeiss had developed during this time was ordered to be used on the production Summarex lenses. The increase in performance over a non-coated lens would have been very noticeable. This would in itself certainly account for some of the time that elapsed between delivery of prototype lenses to Berlin and actual production lenses being delivered. I have not seen the entries for the lenses in 1941. It would be interesting to see if they had the "B" designation and what the code for these lenses was.

I will report any news as it comes in.

Edited by derleicaman
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