Question about the 35 Summaron

[Pythagorean]

Hi folks, I’m looking for a Screw mount 35/2.8 for a Leica III and I notice different minimum focus distances for different mounts. The native LTM minimum is 1 meter. I have seen several lenses listed as screw mount for sale having the minimum distance .7 meters and with the red dot for the bayonet mount which makes me think these are M mount lenses with the bayonet removed. Will these lenses focus properly mounted to my Barnack? I’m not looking for collectors pieces, so if they work I’m not concerned that they are mangled. I know some bayonet mounts also were removable by a small screw.. just not sure if the rangefinder coupling would need to be recalibrated.. thanks for any explanation in advance!

 

[Ko.Fe.]

Any LTM lens as Leica will focus right on M Leica. In general.
Some, if not few Leitz LTM lenses were with M adapter from factory in Wetzlar.
Red dot was common on LTM to M Leitz adapters, those are compatible with any Leitz LTM lens within same focal length.
No calibration is needed in general as long as it is Leitz on Leitz.
But even Leitz wasn't perfect.

 

[David Reynolds]

I assume you know there is a f3.5 LTM version of the Summaron which is well over 50% cheaper than the f2.8 model.

 

[Mamiya_Repair]

You are correct in that the native screw mount version has a 1 meter close distance and the M mount has a 0.7 meter close distance. The other variation is the screw mount version removed from the M3 goggles. The lens on the M3 goggled version can be easily removed from the goggles and you have what appears to be a screw mount Summaron f/2.8 lens. And the lens will fit a LTM body and appear to work, but the rangefinder will not be accurate as the cam in the lens has been modified to work with the goggles. This version can be identified by a close focus distance of 0.65 meters. There is one for sale on ebay right now that is misidentified and won't work on LTM or M mount properly.

 

[Pythagorean]

The other variation is the screw mount version removed from the M3 goggles...

This version can be identified by a close focus distance of 0.65 meters. There is one for sale on ebay right now that is misidentified and won't work on LTM or M mount properly.

Thanks! I have seen the .65m ‘screw mount’ selling on the auction site and on other less-than-reputable Leica user/buy/sell groups.. I actually had that version with goggles on my M3 as my primary lens.

So either of the other .7 or 1m thread mounts will be fine then? That’s surprising to me. All else equal why would anyone opt for the 1m version? I am assuming the .7m will also focus that close on the Barnack.. is that correct?

 

[Mamiya_Repair]

I would go with the .7 M mount version sans M mount. The screw mount version was made in less numbers (around 5 thousand LTM lenses verses 20 thousand for the M mount) so you will pay a collectors premium.

 

[Oldwino]

Do the LTM cameras’ rangefinders couple closer than 1m?

 

[Pythagorean]

Do the LTM cameras’ rangefinders couple closer than 1m?

I’m really still unclear on this. Perhaps I should have framed the question on the ability of the camera to focus correctly with either Summaron rather than the Summaron focusing on the camera.

Either way.. What is the result of moving the focus ring on the .7m Summaron to close focus while mounted to a screw-mount Barnack Leica?

 

[outwest]

Do you mean besides the viewfinder image not looking like the camera image?

 

[grain elevator]

I’m really still unclear on this. Perhaps I should have framed the question on the ability of the camera to focus correctly with either Summaron rather than the Summaron focusing on the camera.

Either way.. What is the result of moving the focus ring on the .7m Summaron to close focus while mounted to a screw-mount Barnack Leica?

The rangefinder uncouples. It will seem like focus is at 1m or thereabouts, while actual lens focus is closer. To me it's not a problem, for some people apparently it's easy to miss that the RF patch no longer moves when focusing.