getting russian lens to work on m-bodies

[raytoei]

i was reading how to shim a jupiter-12 lens (Biogon copy)
to get to focus properly.... the horror ....

(russian lens tend to be back focused on leica bodies, but focus
properly on russian bodies)

the method i chose looked like this:

i added a piece of aluminum foil between the LTM-to-M-adapter and the Lens.

I screwed in the lens to the adapter but not all the way in, then i inserted a
small piece of aluminum foil folded several times and stuck it in between.
I tightened it and tested it on my Epson R-D1, on my 3rd adjustment, i nailed it.

right now the focus is spot on, i am not removing this adapter and lens combination.

This should work for all russian ltm lens with M bodies.

 

[crispy12]

In my experience, this doesn't get focus accurately at all distances. The FSU focusing groove is at a slightly different angle compared to Leica.

 

[mazeppa26]

Photo samples

 

[ricohflex]

Technically called a shim to increase distance so lens rays can focus on sensor.

 

[hydroburn249]

when you say focus accurately do you mean the distance scales corresponding to the focus point?

or if image looks focused in the RF patch means its focused?

In my experience, this doesn't get focus accurately at all distances. The FSU focusing groove is at a slightly different angle compared to Leica.

 

[raytoei]

Russian lens on Russian bodies, focuses and picture comes out focused.

Russian lens on Leica Bodies, usually backfocused, you focus on the eyes, but the picture comes out where the ears are focused.

By putting the foil, i create a slight distance shift so that when i focus on the eyes, the pictures comes out where the eyes are sharp.

hope this helps

raytoei

 

[gbealnz]

Once you establish the thickness required, why not replicate it with something that allows the lens to be removed if you want? Something like a thin piece of teflon sheet, cut neatly, or similar. Piece of foil or gasket, like is used on an engine?
Or can you adjust the infinity stop, within the lens itself? I read somewhere where someone did this with a lens, IIRC a Leica lens, but can't recall why. If I find it again, I PM you.
Gary

 

[crispy12]

Focus at all distances meaning RF aligned at 1.5meters, photo in focus.
Subject at 3m, backfocus by a few CM.
Also depends on the lens type design I think, some might be more susceptible than others.

 

[crispy12]

I shimmed a J9 85mm that had a back focus of about 4cm at minimum focus, accurate at infinity. After shimming it was perfect wide open at minimum focus (for portraits) but at 5m the back focus was about 50cm LOL. There's probably a better way to shim however involves adjust an internal shim, but I'm not confident to open up the lens module.

After that saga I told myself to completely give up on FSU lenses

Also raytoei, not recommended to shim the way you do as the shimming will not be even all around. You can try cutting paper shims from very thin card or paper, they are shaped like a thin ring that goes around the lens. Very thin meaning fraction of a mm.If its too thin then stack a few

 

[gbealnz]

I only have the one R/F body (M8) and three lenses (Leica x3) so my interest in this is passing only. BUT............ there has to be a reason, surely.
If I read it correctly, the indicated focus and the actual focus "vary", depending on where in the focus range (infinity to close up) you are, is this correct?
If so, then it must have something to do with the way the "information" is being sent from the thing focusing (lens) to the thing indicating (View/Rangefinder). If I am not mistaken this is via the "cam" fitting on the rear of the lens mount, as you focus it pushes the roller within the body which actuate the R/F patch movement, correct? If so, can you "modify the cam? I know it is a big job, but why not look at reshaping the cam? If it needs more "height" at the close up end, then add a bit, or better still adjust it so any change means reducing the height, possibly by filing the cam/lobe.
Make sense?
Gary

 

[crispy12]

I only have the one R/F body (M8) and three lenses (Leica x3) so my interest in this is passing only. BUT............ there has to be a reason, surely.
If I read it correctly, the indicated focus and the actual focus "vary", depending on where in the focus range (infinity to close up) you are, is this correct?
If so, then it must have something to do with the way the "information" is being sent from the thing focusing (lens) to the thing indicating (View/Rangefinder). If I am not mistaken this is via the "cam" fitting on the rear of the lens mount, as you focus it pushes the roller within the body which actuate the R/F patch movement, correct? If so, can you "modify the cam? I know it is a big job, but why not look at reshaping the cam? If it needs more "height" at the close up end, then add a bit, or better still adjust it so any change means reducing the height, possibly by filing the cam/lobe.
Make sense?
Gary

Yes this makes sense. This is not possible because most FSU lenses don't have a cam like an LTM or M mount lens, instead it has a focusing tube in the rear which moves closer or away from the body depending on the lens focus. It is parallel to the body and does not rotate, just moves anterior/posteriorly and pushes the RF cam. The tube is threaded and based on the J8 50mm and J9 85mm it is actually the angle of the threads that determines how much this focusing tube moves. IMO it is only apparent on the longer lenses, 50mm on film looks acceptable and only on a digital might you notice.

The lens can be shimmed to work, Brian Sweeny of RFF does it. Can also try local but IMO not worth a CLA, rather get a vintage Leica lens or CV for the money put in.