Summicron Rigid Bayonet + Screw Mount?

[UliWer]

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vor 5 Minuten schrieb Pyrogallol:

This is the March 1960 catalogue and it only shows the collapsible version available in screw fit.

Does your catalogue also list the IIIg? In a brochure for the IIIg from 1958 I find the combination of IIIg and collapsible Summicron as "GOOMI". Perhaps there is a new combination with a rigid Summicron in 1960.

[jc_braconi]

Just to for illustration Summicron is from 1959 1 706 xxx, Summilux is from 1959 1 702xxx
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[Pyrogallol]

23 minutes ago, UliWer said:

Does your catalogue also list the IIIg? In a brochure for the IIIg from 1958 I find the combination of IIIg and collapsible Summicron as "GOOMI". Perhaps there is a new combination with a rigid Summicron in 1960.

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It does not say which version of the Summicron, collapsible or rigid? Edited December 22, 2023 by Pyrogallol

[pgk]

2 hours ago, wizard said:

William, while what you say is correct, it does not tell the whole story. As you say, the lens heads were physically interchangeable between screw and M mounts, but that does not mean that you could simply take a lens head from any screw mount Rigid, insert it in a an M mount or vice versa and go shooting. To focus correctly, those mounts had to be matched to the particular lens head, and that's why Leica, on special request, sold those lens heads with two mounts (screw and M) each bearing the same serial number as the lens head, thus showing that both mounts had been precisely matched by Leica to work with that particular lens head. So what this means is that if the mount (be it screw or M) does not indicate the serial number of the corresponding lens head, the lens head is not matched to the mount and may or may not work correctly with that mount (it is a matter of luck).

Andy

Ummmm. This might well be the case but the reality is most probably that a ny focus mount which matched the focal length of a lens could be used. And from previous posts it looks to me as though there were several indicated focal lengths and these probably worked to a tolernace  rather than being 'precisely matched', meaning that a mount and lens with a similar designated focal length would work together. I would guess that Leica simply matched these up by focal length designation and then engraved the serial number on the mount to ensure that they were a 'matched' pair rather than actually doing anything more.

[UliWer]

vor 1 Stunde schrieb Pyrogallol:

It does not say which version of the Summicron, collapsible or rigid?

GOOMI is the combination with the collapsible Summicron (according to the German "Leitz Gesamtkatalog für den Fachhandel" from May 1959).

It's funny: the same catalogue list only the SOOIC - collapsible Summicron with LTM mount - and expressly says that it was only delivered for cameras with screw mount. So the collapsible with M mount was already cancelled at this time.

In another thread we had a collapsible Summicron with a very early serial number (920xxx) but with M-mount and some signs of later production which was delivered from Wetzlar in 1961.   

So it might be that in the late fifties and early sixties there was still some demand for the collapsible with M mount after this version had been cancelled as well as for the rigid with screw mount. So Wetzlar fulfilled this demand by producing some late collapsibles with M mount and used serial numbers which had already been assigned but were not produced in the original batches. At the same time they produced some rigid LTM mounts as well as some isolated mounts which could be used to swap the (fitting) lens head.

[wizard]

vor 18 Stunden schrieb pgk:

I would guess that Leica simply matched these up by focal length designation and then engraved the serial number on the mount to ensure that they were a 'matched' pair rather than actually doing anything more.

You may well be correct, but even then what I stated above "... but that does not mean that you could simply take a lens head from any screw mount Rigid, insert it in a an M mount or vice versa and go shooting. To focus correctly, those mounts had to be matched to the particular lens head, ..." still applies.

[pgk]

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16 minutes ago, wizard said:

You may well be correct, but even then what I stated above "... but that does not mean that you could simply take a lens head from any screw mount Rigid, insert it in a an M mount or vice versa and go shooting. To focus correctly, those mounts had to be matched to the particular lens head, ..." still applies.

It does, but it would be a relatively simple matter of matching a lens head focal length to a similarly specified focus unit.

My point is that there is no magic about matching things up and there must have been known tolerances which enabled a viable engineering solution.

Edited December 23, 2023 by pgk

[willeica]

22 hours ago, pgk said:

Ummmm. This might well be the case but the reality is most probably that a ny focus mount which matched the focal length of a lens could be used. And from previous posts it looks to me as though there were several indicated focal lengths and these probably worked to a tolernace  rather than being 'precisely matched', meaning that a mount and lens with a similar designated focal length would work together. I would guess that Leica simply matched these up by focal length designation and then engraved the serial number on the mount to ensure that they were a 'matched' pair rather than actually doing anything more.

It was the same with the number under the focus tab of the Elmar in the early days. This was used to get the match with the right mount. The numeric information referenced by the OP was probably for the same purpose. 

The only slight mystery is that while lens heads could be purchased, lens mounts do not appear to have been on sale, but presumably all of this could be handled at the factory. 

This was pioneered when Zuhlcke sent notes to Barnack about tested focal lengths for the early interchangeable Elmars, so by the late 1950s this was a well tried practice in Wetzlar. Ulf Richter wrote about this and produced examples of those notes in his book about Barnack. I met Richter in the Leica Archive in October https://leicasocietyinternational.org/blog/a-visit-to-the-leica-archives-during-the-lsi-wetzlar-2023-conference . One thing we learnt was that the lens records are kept in the Optical Department and not in the Main Archive. So, more research is probably needed at the Optical Department. Whether they have records for what happened around 1959/60 with the M and LTM Rigid Sumicrons is a matter for conjecture. 

William 

Edited December 23, 2023 by willeica

[105012]

Thanks for all the information everyone, very interesting and helpful. So in summary:

• my lens is from a 1959 batch with matching serial numbers on lens head and mount;
• 51,9N is referring to the 51.9mm middle tolerance of focal lengths (with matching "8" marking on mount), the N likely refers to Naheinstellung-Summicron, meaning close focus, however the "zum Teil" indicates that whilst appropriate, not all lens heads where fitted into a DR mount (mine was not);
• the "S" may stand for "Silber" (silver)... although there is reference to some lens heads having AA on them instead, so this is still open...?
• I speculate that the 59 was a short way to write 51.9mm... ?
• the 812376 remains a mystery.

Here are some pictures, as requested by @UliWer:

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[UliWer]

vor 59 Minuten schrieb 105012:

51,9N is referring to the 51.9mm middle tolerance of focal lengths (with matching "8" marking on mount),

Yes. Is there a "8" below the focus knob or elsewhere? 

vor 59 Minuten schrieb 105012:

the N likely refers to Naheinstellung-Summicron, meaning close focus, however the "zum Teil" indicates that whilst appropriate, not all lens heads where fitted into a DR mount (mine was not);

Very improbable, as your's is no "Nah-Summicron" there was no reason to indicate it as such. These scratches only make sense if they are applied only for the lens the "scratcher" has in front of him or her. 

vor 59 Minuten schrieb 105012:

the "S" may stand for "Silber" (silver)... although there is reference to some lens heads having AA on them instead

Certainly not. Since the color of a lens head is obvious from the outside there is no reason to scratch a sign for the color on the inside. The "S" as well as "AA" or "N" probably are the signatures of the people who did the scratchings. "Silver" was never used officially to describe the lenses. It was "Chrom" or "hell verchromt".

vor 59 Minuten schrieb 105012:

I speculate that the 59 was a short way to write 51.9mm... ?

Certainly not as the short way was "19". You'll find the "19" on your lens mount next to "m" or "feet" engraving. Not very probable: the 59 might stand for the year of production??? P.S.: perhaps "S" made a mistake with "59" and "N" corrected it to "51,9" ???

vor 59 Minuten schrieb 105012:

the 812376 remains a mystery.

Yes! Very improbably it could stand for 1.812.376 which is a serial number in a batch for 50mm Summicrons from 1960. But it would be strange that somebody scratched 6 digits and forgot the simple "1". Even if this was true it wouldn't fit the serial number on the front of your lens and for the mount. 

Perhaps somebody with a lens close to your number could look what is scratched inside. For my 211 60 50 I just find this number and the "19" on the lens head. Both are not scratched on the rear end but in the deepening between the lens corpus and the outer chrome socket. On the mount there is no scratching but a  very fine bright engraving or printing which replicates the serial number. 

Edited December 23, 2023 by UliWer

[romualdo]

On 12/22/2023 at 5:36 PM, Pyrogallol said:

As yours has matching numbers on the mount and lenshead then it would have been a bayonet version from the start. It was possible at the time to buy a screw mount to use as an alternative with a bayonet version, but then they would not have matching numbers. Screw rigid Summicron lenses are uncommon now and sell for a considerable premium. To check that they are original you would need to check that the numbers on the mount and lenshead match.

I have a rigid screwmount 50 cron with matching serial numbers (16237xx, head & mount, 51.9N  S hand engraved on head) - I just presumed that if you had a screwmount then you could just add the LTM to M adapter to use it on an M (as I do). So, conversely was it possible to buy an M/bayonet mount 50 plus an extra mount with a screw thread (irrespective of matching number) so to enable use on an LTM camera??

Edited December 26, 2023 by romualdo

[wizard]

Am 26.12.2023 um 06:31 schrieb romualdo:

So, conversely was it possible to buy an M/bayonet mount 50 plus an extra mount with a screw thread (irrespective of matching number) so to enable use on an LTM camera??

Yes, as I had already pointed out above, "if you had bought two mounts (LTM and M) and one lens head from Leitz at the time, both mounts would have had the number of the lens head to show that this specific lens head was matched to work with two different mounts (LTM and M). Those original combinations are extremely rare though."

And as also discussed above, you could not just use any (screw or M) mount with any given lens head, as each mount (screw and M) had to be a mount matched to the focal length of the specific lens head. Leica used the correct matched mounts in the factory when assembling the lenses, and they were obviously in a position to supply correctly matched mounts on request.

 

Am 23.12.2023 um 16:22 schrieb pgk:

My point is that there is no magic about matching things up and there must have been known tolerances which enabled a viable engineering solution.

No, there is no magic involved here, but you need to use a mount that matches with the focal length of your lens head. Leica performed that matching process in the factory when assembling the lenses, and it would be hard to do that yourself, as the lens'es focusing cam will be slightly different from one focal length to the next. It is not a matter of just adding some shims, it is the correct pitch of the focusing cam that ensures correct focusing throughout the focusing range.

Edited December 28, 2023 by wizard

[romualdo]

On 12/28/2023 at 9:29 PM, wizard said:

Yes, as I had already pointed out above, "if you had bought two mounts (LTM and M) and one lens head from Leitz at the time, both mounts would have had the number of the lens head to show that this specific lens head was matched to work with two different mounts (LTM and M). Those original combinations are extremely rare though."

wow!! was never aware of that - would love to see an image of both mounts (LTM/screw & M/bayonet) showing the same serial #