Coupling Problem between Leica M3 and Summicron 50mm 1969-1979 version

[khaichern]

Dear fellow forumers,

This is my first post in RF forum, I hope the forum would welcome me.

I have just bought a Leica M3 and a Summicron 50mm 3rd version separately. The M3 has been converted from DS to SS by the previous owner. The cosmetic condition seems alright and mechanical condition is perfect.

However looking through the viewfinder, the coupling between the lens and camera is very off, the rangefinder patch couldn't move beyond 0.9m (the minimum focusing distance for this lens is 0.7m), and the rangefinder patch & viewfinder patch don't merge together at infinity. After consulting a local camera repairman, he said that the lens has been modified, the metal part that touches the camera has been filed off by other people, therefore the distance between the lens and camera bearing is no longer as original distance.

It seems pretty obvious that I have gotten a faulty lens. However last night I was browsing through other websites and this comes into my eyes: http://photo.net/leica-rangefinders-forum/003oyt .

Below is a comment posted by Al Kaplan:
There is one thing you have to watch out for with this and newer 50mm Summicrons (and wide angle lenses)if you use them on an M3 body. The factory adjusted rangefinder won't focus all the way down to the 28 inches that the lens does. I understand that a repair person can easily modify the rangefinder's focussing range, and probably most have been modified over the years when in for routine service.

This pretty much sums up what happened to me, except that my infinity also has problem. So can anyone who owns or previously owned this lens-camera combination tell me if what the person is true? That you can't focus the lens all the way down to 28 inches if the camera was factory adjusted before?

Thanks a million,
Khai

 

[ottluuk]

I haven't had an M3 but it's pretty common knowledge that they don't focus down to 0,7m/28in 'out of the box'. But they can be modified to do so.

 

[kiemchacsu]

my M3 is original DS and it won't focus closer than 0.9m. I was in similar situation when I mounted it with a Summicron IV. Though focusing on mine is perfect from 0.9m to infinity. I don't mind to use it like that to be honest!

 

[Particular]

My m3 has been adjusted to focus closer than 1m. At infinity the arm with the rangefinder tracking wheel is pushed into the body by the brass ring of the lens. As you focus closer, the lens moves forward, and the tracking wheel follows. On the m3 there is a stop screw that prevents the wheel moving past the 1m point. A repair person can adjust this stop screw or the cam that hits it to swing as far as it will go, which is in my case is about 0.8m. This is a fairly simple alteration, that doesn't have any other consequences.

Filing down the focus ring prevents the wheel from being pushed far enough into the body to reach infinity. It also causes focus to be off over the entire range. I can think of no logical reason why someone would do this, other than vandalism.
Question: Is the ring actually filed down? I.e. Are there tool marks? It is possible that a tinkerer took it apart and put it together incorrectly. If the helical threads of the focus mount jumped a thread, its position will be shifted, resulting in the same problem. A competent repair person could fix that. If it has actually been filed down, then this lens is destined to live on a mirrorless digital body.

 

[nobbylon]

Not so fast! To a none Leica repairman or user the brass contact rings can look like they have been filed however this is how they left the factory. The issue is more than likely the M3 and NOT the lens. Post a pic of the lens where you think it's been filed.

 

[khaichern]

Hi everyone,

Thanks for your swift reply! It leaves hope to me that the lens is not faulty! I will post a photo of the lens highlighting the part where the repairman pointed that it has been filed. It did show some filing mark however, as CNNY said, I couldn't think of any reason the previous owner would file off the lens without knowing the serious consequence by doing so too.

Come and think about it, my body is indeed slightly out of focus, and at infinity the gap difference between rangefinder patch and viewfinder isn't that great, which means the whole system is actually fixable.

Please take a look at the photo and advise me if it has really been damaged. It has some teeth marks. I will take another photo if it isn't zoomed in enough.

Cheers,
Khai

 

[V-12]

The first thing to make a note of is 'never go back to that repair man', the lens looks perfectly normal.

V

 

[Particular]

It looks normal to me too. That ring was calibrated at the factory by grinding it to the right depth.
I think all you probably need is to have the rangefinder on the m3 adjusted and you are ready to go.

 

[SolaresLarrave]

Have you developed a roll? Were your photos sharp and in focus? If so, don't fret. If not, send your camera and lens to a repair man certified by Leica. This will depend of your location. Are you in the US, Europe or Asia?

 

[rodinal]

That lens does not look ok.
It clearly shows a "step" on the RF coupling ring. Your technician seems to be right.
Please, try to zoom the picture at the marked zone and take a more lateral shot to be sure.

 

[Particular]

That lens does not look ok.
It clearly shows a "step" on the RF coupling ring. Your technician seems to be right.
Please, try to zoom the picture at the marked zone and take a more lateral shot to be sure.

My summicron v4 has exactly the same step in the ring. The stepped down part is the only part that has contact with the wheel. It is meant to be that way.

 

[khaichern]

Hi Solares,

The only distance that I can be sure of is infinity, and it turns out alright. For other distance I couldn't know if it's in focus as I am not too sure the exact distance the object is away from me..

Hi Francisco,

I am in Asia and sending the lens to be repaired is likely to cost more than the lens itself. However I will post a close up photo by tomorrow and let you guys judge. CNNY is it possible for you to post your lens photo here showing the same part? I couldn't find that online.

Cheers.

 

[rodinal]

My summicron v4 has exactly the same step in the ring. The stepped down part is the only part that has contact with the wheel. It is meant to be that way.

Now I'm only carrying my "v5" Summicron (the pre-asph) and it does not have any step. If filing part of the ring is/was part of the factory calibration procedure, then it may be right.

I have other Crons at home, v4, DR, rigid and collapsible, and can check them this evening.

 

[Particular]

I hope this clarifies it. You can see where the brass is blackened, and where it was ground down:

 

[rodinal]

I inspected my Crons.
The collapsible and the rigid do not have any step, the RF coupling rings are totally even, same as my v5. The v4 has a ring similar to the one CNNY shows above, with a marked step. The DR is a different story. None of them showed filing marks whatsoever.

 

[Phil_F_NM]

The RF cam on the lens is a simple cylinder with helical threads on the outside towards the inner, optical body of the lens. Leica has two different standards for 50mm lens nominal focal length: 51.6 and 51.9mm. The DR Summicrons and some "rigids" are 51.9mm, while every other 50mm Leica lens is 51.6mm.

They take this simple cylinder and machine in the proper depth in the case of a 50mm lens and in the case of a wide or long focal length, they also machine in the slope of the cam surface. It is cut only about 120 degrees of the complete cylinder because the Leica lens only rotates that much. The rest of the cylinder is there simply to save production cost.

In later lenses like the V5 'Cron, I've not seen a similar cut as I'm thinking Leica simply built in the depth across the whole cylinder. You ask, "why didn't they do that in the first place?" Well, it was only fairly recently that Leica began producing their lenses with extremely precise CNC machines and combining a helical in a cylinder (which needs to be properly oriented for critical focus and optical alignment) with a surface on which a cam follower must rest is really advanced. They used to simply fab up the cylinder, orient the helical according to an index point, then grind the rest of the depth to ensure proper focus. This is also an insurance policy since if they made the helical cylinder too long, they could simply remove more metal but if it's too short, then it is garbage.

This little bit out of the OP's lens cam surface is perfectly normal. My Rigid 'Cron has the same cut. It wouldn't hurt to have the camera and lens collimated though. Happy shooting.

Phil Forrest

 

[khaichern]

After reading all these comments, I feel really relieved. Thanks for your really professional comment, Philip.

Anyway I have attached a few close up shots of the lens, let you guys to judge its condition. Btw it looks exactly the same as CNNY one..

 

[nobbylon]

I just love repairmen who have no idea what they are talking about.
Cars, motorcycles, cameras, they are all the same, useless.
The good news is that the lens is normal and you just need to get the camera adjusted.
DIY, it's not that difficult.

 

[ruby.monkey]

The cut-out on the lens mount itself looks like it's been cut deeper, and none too tidily. Presumably that was done to allow extra travel for the R/F cam follower, to allow closer focussing. That may be what mislead the repairman.

 

[nobbylon]

This first pic is of the V3 at 0.7m clearly showing the ramp on the brass focus face and also uniform file marks to the chromed mount cut out. These same file marks are visible on my Summilux 50 v2 and also my 50 collapsible elmar which I know to have been untouched since leaving the factory.