M2 rangefinder patch weirdness

[qqphotos]

My M2's rangefinder patch seems like its adjustment varies from side to side. That is to say, aimed at a distant subject (or at a close, flat subject), the main and 2nd image will coincide perfectly at one side of the patch or the other but not both.

It's not a huge discrepancy, but certainly enough to be visible on film with a fast 50 or a 90mm F/4 not stopped down.

Is this a thing? Is there an adjustment that may be off? The camera just came back from being serviced. Do I just take a bunch of pictures and try to figure out which side is more accurate? I'm relatively new to M bodies, but maybe I'm spoiled by the rangefinder in my IIIg which is accurate and consistent across the whole rf area.

(i should mention that I'd like to actually understand what's going on internally too)

 

[Erik van Straten]

You say that the camera just came back from being serviced. Just contact these people to send the camera back. A prism in the viewfinder is probably a bit loose.

Erik.

 

[Ronald M]

Also if one side of patch is a different distance such as at an angle, what you observe is correct. If you look at a flat subject and camera back is parallel to subject, something is wrong.

 

[qqphotos]

Also if one side of patch is a different distance such as at an angle, what you observe is correct. If you look at a flat subject and camera back is parallel to subject, something is wrong.

Right, this is why I'm wondering. With a distant subject, the minuscule difference in distance should have no impact at all. With a closer subject sqare and parallel to the film plane, there should be more or less no difference in distance.

The way this manifests itself most obviously is with the focus ring against the infinity stop and looking at the vertical edge of a 2km distant office building, panning the camera a fraction of a degree from side to side (ie moving that vertical edge between the left and right side of the RF patch) the split image will diverge or come together without turning the focus ring at all.

 

[Rob-F]

The way this manifests itself most obviously is with the focus ring against the infinity stop and looking at the vertical edge of a 2km distant office building, panning the camera a fraction of a degree from side to side (ie moving that vertical edge between the left and right side of the RF patch) the split image will diverge or come together without turning the focus ring at all.

That can't be right. It needs to be looked into and corrected.

 

[Richard G]

It is not uncommon for a camera to return from service with a new problem. I have had to return cameras twice and once made the adjustment to the vertical rangefinder in my M5 myself. And they had not been able to fix the original problem either. Depressing.

 

[qqphotos]

That can't be right. It needs to be looked into and corrected.

DAG said he has never seen this and can't even imagine how it could happen, so I feel like sending it to him to correct it would be asking for frustration on both our parts. If I could tell him something like "I think the bracket for prism X is pivoted incorrectly" it might be a little more likely to have a good outcome.

 

[Chriscrawfordphoto]

I bought an M2 last year from Tamarkin that had that issue. I sent it back. Only time I have ever seen such a thing! Return it, it probably cannot be fixed without replacing the whole rangefinder mechanism. Where did you buy it?

 

[qqphotos]

I bought an M2 last year from Tamarkin that had that issue. I sent it back. Only time I have ever seen such a thing! Return it, it probably cannot be fixed without replacing the whole rangefinder mechanism. Where did you buy it?

Leica shop vienna, https://www.leicashop.com. I should have been more cautious buying from them, the camera was in somewhat worse shape than it was represented to be.

I suppose i could return it, though since i've already had it overhauled by DAG, replacing the whole rangefinder may be worthwhile compared to starting fresh with a different camera with other unknown problems.

 

[qqphotos]

Finally set it up on a tripod so i could take pictures through the viewfinder with a phone camera, to demonstrate this weird misalignment.

 

[Chriscrawfordphoto]

Mine was doing the same. You should have returned it immediately instead of sending it off for repair.

 

[qqphotos]

Mine was doing the same. You should have returned it immediately instead of sending it off for repair.

Didn't realize it until I got it back. At any rate, DAG says he's never seen this before and is interested in figuring it out, so I'm sending it back to him for another look.

 

[Rob-F]

Any updates on this?

 

[qqphotos]

Any updates on this?

I got it back recently from DAG after 5 months of calling and asking about it. Nothing is visibly different but it showed up with a note saying he took it apart and it "looks ok". I didn't want to deal with it anymore and sold it. The discrepancy was probably within depth of field for slower lenses so someone less picky probably wouldn't care.

 

[Sarcophilus Harrisii]

Finally set it up on a tripod so i could take pictures through the viewfinder with a phone camera, to demonstrate this weird misalignment.

Somehow, the size of the patch has changed. It's no longer 1:1 relative to the finder. This is why only one side of the building can be crisply aligned at any time. Why this is, I don't know. Can only hazard a guess one of the internal lenses between the deflecting prism, and the main prism itself, has shifted, and altered the relative size of the patch? Interesting fault.

 

[qqphotos]

Somehow, the size of the patch has changed. It's no longer 1:1 relative to the finder. This is why only one side of the building can be crisply aligned at any time. Why this is, I don't know. Can only hazard a guess one of the internal lenses between the deflecting prism, and the main prism itself, has shifted, and altered the relative size of the patch? Interesting fault.

Thanks, I think this is the first I've seen anyone speculate on what the actual problem could be, though a number of people have reported having similar misalignments. I suppose it's a thing you could easily not even notice, but I'm sort of obsessive about maximizing detail and resolution so I found it pretty noticeable. Unfortunately I think it's something that has very little chance of being repaired without replacing the entire rangefinder mechanism, at least not by any of the usual repairers.

 

[Sarcophilus Harrisii]

Thanks, I think this is the first I've seen anyone speculate on what the actual problem could be, though a number of people have reported having similar misalignments. I suppose it's a thing you could easily not even notice, but I'm sort of obsessive about maximizing detail and resolution so I found it pretty noticeable. Unfortunately I think it's something that has very little chance of being repaired without replacing the entire rangefinder mechanism, at least not by any of the usual repairers.

I can relate to that. I have been doing all my own rangefinder calibrations for some years (and occasionally for others, too) and I am a bit of a perfectionist. Such an issue would drive me mad and I'd also want to eliminate it. If I couldn't, it would be a constant irritation, regardless of the actual consequences of such a fault, in use.

 

[qqphotos]

I can relate to that. I have been doing all my own rangefinder calibrations for some years (and occasionally for others, too) and I am a bit of a perfectionist. Such an issue would drive me mad and I'd also want to eliminate it. If I couldn't, it would be a constant irritation, regardless of the actual consequences of such a fault, in use.

Exactly this. I have a similar problem with shutter issues; I know the uneven shutter travel will only be noticeable on skies or other uniform areas, but it still irritates me to the point I don't want to use the cameras.

 

[Freakscene]

Somehow, the size of the patch has changed. It's no longer 1:1 relative to the finder. This is why only one side of the building can be crisply aligned at any time. Why this is, I don't know. Can only hazard a guess one of the internal lenses between the deflecting prism, and the main prism itself, has shifted, and altered the relative size of the patch? Interesting fault.

Yes, it can only be that one of the angled optical elements in the rangefinder path is in the wrong place. The changed size of the RF patch suggests a linear shift along the optical path, but the lack of focus across the patch suggests an angular deviation from the correct position, so it is probably both. It may be very slight. The condenser lens on the RF mask is the most easily shifted, but the RF objective lens has a rotational adjustment and its mount could be bent. It is a very curious problem. It would drive me mad too.

Marty