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Small "19" beside m on distance scale Black Rigid Summicron


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Hi All,

Can anyone tell me what the small, vertical "19" beside the m on the distance scale of some lenses is for?  I've observed it on several Leica lenses, so I know it's not rare, but I don't know what it is. In this case, on a black, rigid 5cm Summicron.

 

 

Thanks!

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Hi All,

Can anyone tell me what the small, vertical "19" beside the m on the distance scale of some lenses is for?  I've observed it on several Leica lenses, so I know it's not rare, but I don't know what it is. In this case, on a black, rigid 5cm Summicron.

 

 

Thanks!

 

The lens is of nominal 5cm focal length, but this is an indication of the deviation of the actual focal length from nominal (not important except for very specialised applications I suppose.) I can't remeber whether that makes it 51.9mm or 50.19mm (probably the former).

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Hello George,

 

Welcome to the Forum.

 

The small 2 digit number on the lens barrel is the last 2 digits of the actual focal length, measured in 1/10th's of a millimeter, of the lens in your hand. So "19" on the barrel means this is a lens with an actual focal length of 519  1/10th's of a millimeter which is the same as writing 51.9 millimeters.  

 

Leitz/Leica lenses of less than 50mm do not show this measurement. Lenses 50mm & longer (reflex & rangefinder) often, but not always, do. I think the practice of engraving the actual focal length to the closest 1/10th of a millimeter on the lens barrel where it can be easily seen began about 1960.

 

Separable lenses have this  (engraved, written, etc) on both components.

 

Best Regards,

 

Michael

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Hello Again George,

 

Actually, you have a relatively rare version of an otherwise somewhat common lens.

 

The lens in your photo is an early knurled & dimpled version of the 6 element Summicron which replaced the "Rigid" version.

 

Most of the lenses of this optical configuration had a focusing collar which was knurled but not dimpled.

 

Best Regards,

 

Michael

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Hello George,

 

Another thing about the lens in your photo is that it is 1 of the lenses that comes apart so you can use the lens elements without the focusing mount together with other accessories for a variety of applications.

 

If you hold the lens by the bottom with 1 hand (Better done with a rear lens cap on.) & use your other hand to hold the optical unit in the front by the aperture setting ring. And then turn your hands as if you were opening a jar of pickles GENTLY*. The 2 components should separate. If they do not come apart easily come back & tell us & we can figure out what to do next.

 

* Jars of pickles & lenses are in many ways similar to people: If you are forcing them you are probably doing the wrong thing.

 

Once the 2 components are separated you should see the same 19 on the separated optical section & the serial number of the optical unit on the focusing mount.

 

Best Regards,

 

Michael

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And that is an important part of the need for the engraving of focallength on the system, the focus mount has  to match the focal length of the lens unit to get proper rangefinder operation, the two halves should have the same numbers 'sccratched' on the internals when you get them apart.

 

Gerry

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Sorry for the poor quality of those photos, but I couldn´t resist

Summicron 1:2 / 50 sn 1886xxx

Best regards

Antonio

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Hello Antonio,

 

Welcome to the Forum.

 

Thank you for the nice photos of the matching "19's".

 

This "Rigid" Summicron, which was the predecessor of George's lens above, sometimes had the serial number engraved within the focusing mount.

 

Please also note: 1 difference between the 2 focusing mounts is that the skirt on this lens tapers from the focusing mount barrel to the point of contact with the camera body while George's lens has a skirt which is parallel to the focusing mount barrel. 

 

Best Regards,

 

Michael

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Three thougts about "19" engravings:

 

1 - James L. Lager, Leicas An Illustrated History, volume II - Lenses, shows: 

 

a) - pg. 55 - a sm  Summicron focusing mount (feet and meters) with engraved "19".

B) - pg167/168 - three bm Summicrons  (feet and meters) with engraved "19".

c) - pg 170 - two bm Summicrons (feet and meters) with engraved "22".

 

2 - Some (two I think) feet and meters had no "19" or "22" engraving, but NO feet scale only have that kind of engraving.

Only fett and meters scale.

 

3 - Strange it is.

 

Regards

Antonio

Edited by Antonio Madureira
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Hello Everybody,

 

Lenses manufactured before about 1960 did not have these additional external engravings.

 

I think that most, if not all, of the DR Summicrons did not have the 19 engraved on their barrels because: I think most, if not all, of those special focusing mounts were made to accept those lens heads that were 51.9mm in actual measured length. Don't forget that the actual physical focusing mount of a DR is much more complex & difficult to build.

 

If the majority, or all, of the lens mounts were only built to 1 standard, then: Only the lens heads themselves would need to be marked to be compatible. 

 

Best Regards,

 

Michael

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