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"My Russian lens focuses correctly on a Leica" - Oh no it doesn't

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It never fails to amaze me that some folks still insist that "Their" Soviet period LTM lens focuses perfectly at all distances wide open on a Leica body camera. They will produce small thumb nail images to prove this, all taken with undisclosed apertures at a single distance. Why won't they believe that this is just physically impossible, unless the RF cam has been expensively built up and reground. This is for the very simple reason that historically, going back to the 1920-30 period, when Zeiss assisted with technical advice to the nascent Soviet camera lens industry, the Soviets opted to use the Zeiss focusing helicoid thread pitch. This is different to the helicoid thread pitch, which Leica have used, since they first made LTM (39mm x 26 t.p.i.) removable lenses in the 1920's. If you look at the back of a Soviet era RF coupled LTM mount lens, you will see that the rotating RF cam is curved, not flat like the Leica rotating cam on their single helicoid lenses, e.g any of the Summicron 50 lenses series 1 LTM to series V M mount. For those of a technical bent, Dante Stella explains this at some length but very clearly here: https://www.dantestella.com/technical/compat.html .

I have referred people to this article and they come back still believing that their Soviet lens is different. I can only assume this is a form of self delusion and not wanting to admit, even to themselves, they have bought the wrong lens for their camera. Yes they may be in focus at certain distances and may work acceptably when well stopped down but that is all. I always tell people looking for a "cheap" lens for a Leica camera - buy Japanese. The Japanese camera industry opted to use the Leica helicoid thread pitch on RF demountable lenses, even for the Nikon Contax type RF mount, which is, of course, why the Nikon lenses do not focus correctly on a German Contax RF camera body. These Japanese LTM lenses focus perfectly on Leica and Leica type bodies, LTM and M mount with an adapter ring but not on Soviet LTM bodies. 

The only exceptions to the above are the recent re-issues of classic Russian Jupiter lenses by Lomography. They have now been optimised to focus correctly on Leica and other similar bodies (Voigtlander, Konica Hexar, Zeiss ZM, etc). Conversely, these new lenses will not now focus correctly on a period Russian body (FED, Zorki, etc). 

Wilson

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Posted (edited)

Very interesting and informative. I have just read this immediately after posting my latest experiences matching my non-standard Elmar with a similarly non-standard FED body. 

Edited by Pyrogallol

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Posted (edited)

Thank you Wilson.

A timely piece of advice.  My 3f is 'away for c.l.a.' and I don't expect to see for at least 3 months; 6 months when I sent it.

I have been toying with buying a stand-in body and have been reading up on Fed with a view to using my Leitz lenses.

I do have a second 3f but that has colour neg. in it. The one away I use for mono.

I might just keep on mooching and humming until my own returns.  Saves me a penny or two.

D.Lox

Edited by Jerry Attrik
trying to reduce the line spacing ???how?

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interesting article, indeed. Will need some time to read and understand :-)

But in one thing he is not quite correct: when Leica made the dual-range Summicron, it made focusing mounts for several different actual focal lengths. Then optical units could be matched with the mounts that would focus them the most accurately.

It was much earlier, already Elmar 5cm had different mounts for different focal length - focal length group stamped beneath the focus tab

 

 

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Part of the issue likely is the "sled" on the focus arm rather than a roller. The distance between the pivot and the contact point of the rangefinder arm stays the same with a roller. With the flat slider, the distance between the arm pivot and the contact point on the lens cam changes, which has been calculated in the soviet camera/lens combo. This is all interesting to me because I have a 50mm f1.5 Jupiter 3 that when used on a Sony A7 was one of the sharpest of the 50mm LTM lenses I tested. But used on my Leica IIIc, it was horribly soft wide open up close but seemed much better at infinity. I have a zorki that works well and think I will give it a try on that body.

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Posted (edited)

Fully agree. My only point here is that nowadays there is a culture of "good enough". Today we consider that things like rebooting from time to time is acceptable and, even more, that such device is working.

So, unfortunately, as per today standards they work. Of course, when you compare them with the real thing that really work, where the precision is everything, adjusted and tested one by one, the difference is amazing.

I have a few Soviet lenses and cameras (some early samples as well as some samples from right after WWII) and they can have some interest but let's keep in mind that they are what they are. They even not screw properly in the mount of a Leica screw.

So once more, fully agree but I'm afraid it's a lost war.

Best regards

Edited by tranquilo67

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I believe some Russian M39 lenses are 1mm thread pitch rather than 26 threads per inch. 1mm thread is equivalent to 25.4 threads per inch. If both the "Leica" camera body and Russian lens are well worn, these lenses may mount OK, otherwise they will often bind after about two turns. The LHSA and I did some research about 9 months ago on the origin of the 26 threads per inch on the Leica M39mm lens mount, when a 1mm thread pitch might have seemed more logical. It is probably due to the fact that Leica were a microscope and attendant lens maker, long before they were a camera maker. Firstly it was a convention (still applicable today) that microscope objective lenses use imperial threads (26tpi was in common use) and secondly the machinery to cut those threads was often made in Great Britain with no metric thread capability (127 tooth change gear needed). It is believed that the thread cutting machinery in use by Leica in the mid 1920's, was not metric. 

Wilson

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I have just had a quick look on a couple of auction sites, a Japanese one and eBay. There are 35mm Canon LTM lenses for sale in considerable numbers and various apertures. There are some at less than £200. IMHO a far better buy than a Russian to use on a Leica or Leica compatible body. 

I have just had a look at the latest Wetzlar auction catalogue and I see they are expecting high prices for early Russian FED and  Chinese Zhongi cameras. That will teach those people who converted them into Leicas 😀

Wilson

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Hi Wilson

Agree with you regarding Canon ltm's from Japan.  I have quite a few and always buy from Japan.  The dealers present their lenses immaculately and usually truly represented. Very good lenses with lovely build.

...

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And as far as a backup body for a Leica, I would also recommend buying a camera made in Japan. Honestly am not super impressed with the Canon Barnack clones (but the later ones are OK/better than any russian models), and the Minolta isn't any better. But the later Canon L1 (and some of the other models from that time) is a jewel of a camera. While not as compact as a Barnack style, has a built in rotating finder feature that allows it to natively work with both 35mm and 50mm lenses, as well as zoom in for focusing. The back opens for loading like a film SLR which is also very nice. For a Barnack clone, look at the Tower/Nicca LTM models. Very solid camera and some of the later ones were made with a lever wind. The model 5 even has a back door like an M to make the bottom loading easier. I recently picked up a Tanack which is off for a CLA. I haven't used it yet but this also feels like a solid Barnack style camera, but has an opening back like a film SLR, which makes loading so much easier.

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