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LTM (ЛТМ) ≠ Leitz LTM


01maciel

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I recently bought an old Helios 44 2/58 LTM only to find that it won't focus on the M10 with any of my LTM adapters. A quick internet search revealed the fact that the Russian LTM thread is not compatible with the Leitz thread. The lens can only be used with another LTM->M42->M adapter but not coupled with the rangefinder. Why is that? Weird, after the Russians took the patents with them after WWII, they could have stayed with the standard valid at that time but they didn't. Now my question: are there any more of these LTM problems with the old Russian lenses?

 

Edited by 01maciel
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13 minutes ago, 01maciel said:

Now my question: are there any more of these LTM problems with the old Russian lenses?

In short, yes. As a general rule, FSU Zenit SLR lenses in LTM mount won't play nicely with the rangefinder. The register (flange distance to film) was different - and so was sometimes the thread pitch. FSU lenses designed for rangefinder cameras (e.g., J-3, J-8, I-22, etc.) suffer from similar issues, but to a much lesser degree and can usually be satisfactorily adjusted. 

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vor 1 Stunde schrieb 01maciel:

Helios 44 2/58 LTM

I fear it was only called „LTM“ by a salesman. „LTM“ is sort of internet slang for „ Leica M39 threadmount“, but the first version of the Zenit SLR also had a M39 mount before they went to apply the universal M42 mount. 

If you find out for which flange-to-film distance the lens was made and if you happen to own old Visoflex parts you might be able to construct your own adapter combining some of them.

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Posted (edited)

Or buy the 17 blades Biotar 5.8cm in black paint and a M42-M adapter. You will still not be able to use RF, but at least you will have a piece of history, the very lens Helios 44 was formed upon (presumably another Taylor, Taylor & Hobson, now Cooke based design, first produced before the war in 8 aperture blades version and available in 17 blades version from '46-'52). I love mine but sadly cannot get it converted - Skyllaney said they do not have the tools for the challenge.

Edited by Al Brown
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13 minutes ago, Al Brown said:

Or buy the 17 blades Biotar 5.8cm in black paint and a M42-M adapter. You will still not be able to use RF, but at least you will have a piece of history, the very lens Helios 44 was formed upon (presumably another Taylor, Taylor & Hobson, now Cooke based design, first produced before the war in 8 aperture blades version and available in 17 blades version from '46-'52). I love mine but sadly cannot get it converted - Skyllaney said they do not have the tools for the challenge.

I recently bought one, after dismantling it I came to conclusion that the exa version is easier to convert, its small size makes it easier to fit in old helicoid. You can always get shoten adapter with rf confirmation. 

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30 minutes ago, Carlos cruz said:

You can always get shoten adapter with rf confirmation. 

Apparently no, Shoten M42-M adapters ONLY work properly with exactly 50mm lenses I was told. This one is 58mm...

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Thanks for all your comments and advice. I ordered a Lens Mount Adapter ring, M39 --> M42 (39 mm – 42 mm thread) from Amazon. It's actually a mess since I use two adapter for this lens. First tests with the EVF have shown that focussing isn't a problem anymore. Some photos can be expected very soon 😄.

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He didn't like the lens at all. But at least he sat there calmly for the photo, albeit annoyed. Incidentally, he is the only model in the wider area that doesn't do it for money. He only takes treats.

M10 + Helios-44 LTM SLR

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23 hours ago, UliWer said:

„LTM“ is sort of internet slang for „ Leica M39 threadmount“,

LTM is NOT M39.  LTM is 39mm diameter by 26 threads per inch (tpi).  LTM should be referred to as L39.  M39 is 39mm diameter with a metric pitch.  There are coarse and several fine metric pitches that are part of the metric M39 DIN spec.  Leica lenses, ignoring Visoflex lenses, are also 28.8 mm from the rear lens flange to the focal plane, called registration.

To be compatible with Leicas, a lens must have 39mm diameter, 26 tpi, 28.8mm registration and compatible RF coupling.  The Soviet manufacturers used an RF coupling that sometimes can be incompatible with Leicas.

The other manufacturer that was deviated from the definitive L39 thread was Canon.  Their original J series lenses were M39 x 1.1mm pitch, then they made a Universal 39mm mount that would work on either camera by using sloppy threads.  (Peter Dechert, Canon Rangefinder Cameras 1933 ~ 68, pg 14.)  Canon finally settled on true L39 in 1952.  The J series may have been different to avoid any legal action from Leitz.  After WWII any manufacturer could use Leitz intellectual property with fear of legal action.

The only camera I know of that is true M39 is the Braun Paxette, but with a different registration.  One of the Compur shutter sizes is M39.

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I wonder what focal length the Helios 58mm with the extension of the adapters M39->M42->M has at the end. How can this be determined or calculated?

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