Collimation of Leica M lenses

[Makten]

Some of you might have read this thread: http://www.rangefinderforum.com/forums/showthread.php?t=85203

To sum it up, it looks like my Summicron-C 40/2 doesn't reach infinity because it's not properly collimated. That means that the optical cell isn't at the right distance from the bayonet mount, which also makes focus being off at the whole usable range.

I know that the Summicron-C is said to have focus issues with M cameras, but that's a later problem. Right now I want to try to collimate it, which seems to be done by adding or removing shims to move the optical cell in its barrel. Should be quite easy theoretically.

Now; the problem is to get the right pieces of the lens apart. I presume that a Summicron 35/2 is built in sort of the same way, so if you have any experience on one of those I'd like to hear about it! Any help is very much appreciated. 🙂

Here's a picture of the lens from the rear. There's two retaining nuts inside the brass barrel with the cam slope, and I guess one of those must be unscrewed. But which one? I don't want the rear group to fall out. 😱

 

[Ronald M]

Someone has had this lens apart befor. Look at the butchered screw slots on the mount. A good repair person would use the right tools and not do this.

Since you not only have a focus issue, but a corner issue, I think certain elements are out of position or have been swapped with another sample, which really should not be done, and collimnation will not fix it.

This is a job for an expert to put right if it can be done.

 

[Makten]

Someone has had this lens apart befor. Look at the butchered screw slots on the mount. A good repair person would use the right tools and not do this.

So what? I've had the mount off, and that has nothing with the collimation to do. I have no idea if it was me that "butchered" the screws, but there's nothing wrong with their function.

Since you not only have a focus issue, but a corner issue, I think certain elements are out of position or have been swapped with another sample, which really should not be done, and collimnation will not fix it.

This is a job for an expert to put right if it can be done.

This is not the information I was asking for. I wan't to collimate the lens. Can someone help me instead of telling me how useless it is to try? :bang: Why would you need an "expert" to change shimming?

 

[Sonnar Brian]

1) I have never taken one of these part, and do not know how they are constructed. Looking at the retaining ring with the different sized slots, that would be my WAG of how the optics module is held in place. I am NOT going to take my perfectly working lens apart to find out. That ring was made to go with a special repair tool for the lens. It is not standard.

Not all lenses used shims. Some are custom machined for the mount. Some will turn the indexed Cam for focus correction. I like to work on the Russian lenses and 1950's lenses from manufacturers "other" than Leica. The Leica lenses tend to be less intuitive for home repair. I have taken apart collapsible Summicrons and a Type 1 Rigid Summicron, but for cleaning internal haze.

 

[Makten]

1) I have never taken one of these part, and do not know how they are constructed. Looking at the retaining ring with the different sized slots, that would be my WAG of how the optics module is held in place. I am NOT going to take my perfectly working lens apart to find out. That ring was made to go with a special repair tool for the lens. It is not standard.

That's what I suspect too, and I'll make a tool for it and try it out. I haven't really got anything to lose since it will probably be more expensive to send it for repair than to buy another one.

Not all lenses used shims. Some are custom machined for the mount. Some will turn the indexed Cam for focus correction. I like to work on the Russian lenses and 1950's lenses from manufacturers "other" than Leica. The Leica lenses tend to be less intuitive for home repair. I have taken apart collapsible Summicrons and a Type 1 Rigid Summicron, but for cleaning internal haze.

Hmm, in that case I'll have to mill the front side of the mount a bit. But then I'd also have to adjust the cam.

 

[ampguy]

Ok ...

Ok ...

I'd guess, that having it properly collimated by someone who has done this lens many many times, would not cost more than it's value, maybe 20% or so, you might want to ask around.

If you do end up selling it someday, make sure to mention that it is in "Minty" condition, to keep consistent with the whole used lens game of "old maid" going on ... 🙄

That's what I suspect too, and I'll make a tool for it and try it out. I haven't really got anything to lose since it will probably be more expensive to send it for repair than to buy another one.


Hmm, in that case I'll have to mill the front side of the mount a bit. But then I'd also have to adjust the cam.

 

[Makten]

I'd guess, that having it properly collimated by someone who has done this lens many many times, would not cost more than it's value, maybe 20% or so, you might want to ask around.

Unfortunately, I'm sure that's not the case here in Sweden. I had this particular lens relubed, and that was ~100 bucks. This was before I knew about the problems.

If you do end up selling it someday, make sure to mention that it is in "Minty" condition, to keep consistent with the whole used lens game of "old maid" going on ... 🙄

Haha! No, I'm always honest when selling "bad" lenses. 😎🙂 But right now I find it a good opportunity to try to fix it myself, just because the lens isn't worth very much. If I fail, the experts may take over. 😀