summicron 50 collapsible LTM range patch not aligned

[edwliang]

hello everyone,

i just bought a summicron 50 collapsible ltm with s/n of #134xxxx and noticed that range finder patch is not aligned at infinity. This is the only 1 lens i have come across has this problem among my other leica m lenses.
The patch passed over infinity, that means the rear brass ring(rf focus mechanism, dont know what it is called) is longer than it should be.

is there any way to get it fixed? or i have to trim the rf coupling ring a bit so that it is aligned?

Thanks a lot.

 

[santino]

Is the real picture in Focus at all distances?
If yes then I would live with the small Imperfection...

 

[edwliang]

Is the real picture in Focus at all distances?
If yes then I would live with the small Imperfection...

i used a tripod and did a side by side comparison with adapting to my sony a7. I used sony a7's LCD enlarging to detect the lens' scale and compared it with my m2's range finder patch alignment(my M2 has been CLA, and all my other lenses are aligned at infinity). As a result, the lens range finder coupling system is not accurate. as mentioned above, its rear brass ring is indeed a little bit thicker/longer than it should be.

regards

 

[Mjd-djm]

If you’re using ltm lenses on an M camera (you mention your other M lenses) then you will be using an adapter. These adapter vary in quality and tolerances. Leica and Voigtländer adapters are more expensive but are normally spot on. Cheap imports are usually off and can not achieve infinity focus or sometimes even focus past it. Invest in a good one.

 

[Rob-F]

Could be the lens has been taken apart and not reassembled correctly.

 

[santino]

The Adapter thing sounds reasonable...

 

[edwliang]

If you’re using ltm lenses on an M camera (you mention your other M lenses) then you will be using an adapter. These adapter vary in quality and tolerances. Leica and Voigtländer adapters are more expensive but are normally spot on. Cheap imports are usually off and can not achieve infinity focus or sometimes even focus past it. Invest in a good one.

hello, thank you for reply. the adapter is no problem, i tried other ltm lens with it and works correctly. and i use sony a7 with this same adapter to test the lens.

regards

 

[edwliang]

Could be the lens has been taken apart and not reassembled correctly.

i am thinking of this problem too.

 

[jonmanjiro]

At what distance on the lens distance scale does the patch line up at infinty through the viewfinder?

 

[edwliang]

At what distance on the lens distance scale does the patch line up at infinty through the viewfinder?

between 100 feet and ∞.

 

[jonmanjiro]

between 100 feet and ∞.

That amount of error is within the depth of field of the lens.

When a 51.6mm lens is focused at 145 feet, at f2 the depth of field goes from 72.3 feet to infinity.

I doubt you'll see any focus errors on film.

If it really bothers you, you could grind off some of the focus cam using very fine sandpaper on a flat hard surface. You place the lens on the sandpaper so the focus cam is in contact with the sandpaper surface, and then move the lens in a circular motion on the sandpaper to grind metal off the focus cam. Do it in small increments and check progress on the camera. You don't want to go too far because you can't put metal back on if you grind too much off.

 

[mdarnton]

Are the photos still in focus even though the RF appears to be off? If so, it's not the lens.

I wouldn't grind on anything. One layer of magic tape on the face of the adapter will probably be enough to fix the problem. Since it's a 50mm, the whole range won't be messed up by this as would some other focal length.

 

[David Hughes]

Hi,

In your shoes I'd get it checked and repaired or adjusted. It won't cost the earth and that'll be one more good lens out there.

Regards, David

 

[Rob-F]

One layer of magic tape on the face of the adapter will probably be enough to fix the problem.

What is magic tape, and where can i get some? Sounds like something I should know about!

 

[edwliang]

maybe it will be more tolerant on film than i inspected its acuracy on a7 at F2, i will develop a roll when i have time. thank you all.

 

[edwliang]

What is magic tape, and where can i get some? Sounds like something I should know about!

can try to place a cropped 'memo sticker' between the lens and the adapter

 

[edwliang]

Hi,

In your shoes I'd get it checked and repaired or adjusted. It won't cost the earth and that'll be one more good lens out there.

Regards, David

i contacted my local repairer and he said this problem could not be fixed. i may ask other repairers.

 

[edwliang]

Are the photos still in focus even though the RF appears to be off? If so, it's not the lens.

I wouldn't grind on anything. One layer of magic tape on the face of the adapter will probably be enough to fix the problem. Since it's a 50mm, the whole range won't be messed up by this as would some other focal length.

with the same scale indicated on the lens, it is in focus on my m2's rf, but off on my a7 at F2. (aiming on the same target with a tripod)

would the film have a wider DOF than digital sensor? i havent finished a roll and will see how it affects on still image wide open on film.

thanks

 

[rfaspen]

i contacted my local repairer and he said this problem could not be fixed. i may ask other repairers.

I suspect your local repairer is wrong. Very interesting he/she would say that.

Please don't grind anything on the lens. I doubt that is the appropriate solution. A very thin shim on the face of the adapter is a good start. I think Magic Tape is the same as Scotch Tape here in the western U.S. You can apply the tape (as a single layer, no overlapping strips) to the outer face of the adapter (the part that will mate with the lens when screwed on). It could then become a "permanent" repair for you.

As mentioned in other posts, I suspect the lens may have been "serviced" at some point in its history, and reassembled incorrectly. Its unusual for lenses to be "knocked out of standard" with a bump or drop and not have very obvious collateral damage.

If you want to have the lens calibrated to factory standards, there are a number of well-known Leica technicians who can do that. You'll see the big names here on RFF frequently and they are all good. For this particular issue, I can suggest Youxin Ye as probably the lowest cost with perfectly good work. There are also numerous quality repair techs scattered about the globe whose names we don't often see here, but I suspect your local repair person is not terribly well-informed about rangefinder cameras.

Youxin Ye is in Massachusetts. You'll find him with a Google search on his name.

 

[mdarnton]

Magic tape is Scotch's thin, matte tape, as opposed to the thicker, glossy kind. Other solutions may be too thick---magic tape is really quite thin, and nearly invisible, too.