Rangefinder Alignment Discrepancies (Cameras and Lenses)

[brad_k]

Advertisement (gone after registration)

I recently got a few lenses (50mm Summicron v3, 35mm Summicron v3) back from a CLA and was testing them out on my M6 (silver). I noticed that on a few of them the rangefinder patch didn't align at infinity. This camera, the silver M6, usually has a Voigtlander 35mm 1.4 mounted to it. And with that lens, it does focus to infinity. The v3 summicrons focused correctly to infinity on my black M6.

That led me to believe that the camera body (M6 silver) needed to be aligned. 

But, I was curious about the Voigtlander 35mm lens, and how it seemed to focus correctly on the silver m6. I tried the Voigtlander 35mm lens on my other M-mount bodies (black M6, M2, and M3) and the Voigtlander focused past infinity on each of those bodies. 

All of my M bodies have been CLAd in the last 5 years. And the Voigtlander was supposedly checked at that point (2019) by Youxin Ye. The Silver M6 was also serviced by Youxin at that point.

I guess I'm stumped and frustrated. Are my expectations off base? I haven't noticed things too far out of whack with my photos, but I shoot film, and when I miss focus I just blame it on my, not on the camera. And I don't often shoot wide open. 

I've attached a picture of a spreadsheet I put together that kind of shows how my lenses are aligning at infinity with the rangefinder patch. It's, of course, all of the place. But I've noticed that the Voigtlander 35mm seems focus past infinity on most cameras and that the silver m6 has the most lenses that don't quite reach infinity. And this leads me to believe that I should have both body and lens looked at again.

But If this is all "margin of error" stuff and "to be expected," I'd really like to know.

Thanks! This is somewhat of a rambling post, I hope that the attached spreadsheet helps some.

On the spreadsheet:

O = aligned (according to patch)

+ = past infinity (according to patch)

- = doesn't reach infinity (according to patch)

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

Edited October 28, 2021 by brad_k

[a.noctilux]

Welcome here,

difficult to give you valid advice, you have done so much.

 

I had the same trouble in the past with my multiple Ms, lenses, but I learned to know better my gear, with one combo each time and real use.

It took me some times to learn and admit that those are built with more or less tolerance and the thing can shift with time.

Some tolerances must be thinking of.

Film has some thickness, adjustment of focussing in the film day may take this thickness into account.

So many other parameters, like curvature of field, shift of plane of best focus with aperture and so on that only real use can say if it's tolerable or not.

 

I understand that the "pin-point" may be better for peace of mind for such (or thinking as such) precise (expensive) instruments.

 

As side note, I trust my first 50mm ( Cron version III) M lens and make it my reference lens when I have some doubt with other.

Maybe this reference is out of whack but in real use, I have nothing to complain, that is enough for me, good results count most than measurement.

 

Edited October 28, 2021 by a.noctilux

[Advertisement]

The Leica Q3 is available for pre-order at B&H Photo Video and Adorama

[brad_k]

Thank you for that advice, it speaks to the heart of my question.

[jaapv]

This is exactly the reason that you should send your whole system to a trusted repair shop for calibration, both lenses and bodies. As soon as some lenses are adjusted to some bodies you have lost the calibration  to the common standard. Older lenses and bodies are often set to wider tolerances which can be corrected. 

[brad_k]

Yes, I can appreciate that, though it's disappointing to think this is the only way. I've always assumed that a body gets adjusted so that it works with all lenses. And that lenses are calibrated to work on all bodies.

[a.noctilux]

14 minutes ago, brad_k said:

Yes, I can appreciate that, though it's disappointing to think this is the only way. I've always assumed that a body gets adjusted so that it works with all lenses. And that lenses are calibrated to work on all bodies.

I think it's the case, when they leave the factory new.

Leica made for their best to have it worked as it should.

With time, as I wrote, those may shift.

 

I've read that with transport (or just some time of use, vibrations , wear, etc. ), the calibration can be out of tolerance to be adjusted.

In the past, I need to tell the repair person to adjust some M or lenses once in a while, when CLA.

OR ...

Another 'test', very simple if you have digital Leica M and liveview.

Comparing the distance and real image forming on the sensor can be very instructive.

Edited October 28, 2021 by a.noctilux

[brad_k]

Advertisement (gone after registration)

Sadly I don't have a digital M camera.

What frustrates me is that all of these Bodies and Lenses (with the exception of the two Voigtlander lenses and the LLL 35mm Replica) have had a CLA within the last 3 years. Most were done more recently.

In any case, what I'm going to do is send the chrome M6 and the 35mm voigtlander to a tech to check their calibration using his equipment. And the rest will just have to be okay.

[Matlock]

59 minutes ago, jaapv said:

This is exactly the reason that you should send your whole system to a trusted repair shop for calibration, both lenses and bodies. As soon as some lenses are adjusted to some bodies you have lost the calibration  to the common standard. Older lenses and bodies are often set to wider tolerances which can be corrected. 

Of course you could have a serious falling out with your trusted repair shop when you turn up with 7 bodies and 22 lenses. 😀

[brad_k]

Haha. That's the worst case scenario. And the best case is you get a huge bill in the mail.

[a.noctilux]

And if the transport(er) responsible of decalibrated well calibrated gears when return to you ?

...

Anecdote,

some years ago, I know one repair person did not repair some brands ( Minolta or Konica I don't remember) with rangefinder anymore,

when he resent the calibrated cameras to owners, a couple of last time owners recalled that the job was NOT done.

He realized that the transportation was responsible of the 'not done' ex good job.

 

Myself, as motorcycle traveller, I must transport with care (cushions, foam) my photo apparatus.

Vibrations from flat-twin ...

[brad_k]

What can I do but "shrug" in response to that statement. The thought has crossed my mind, but I can only double-box my packages and cross my fingers. There are no shops that I can drive to. Though I may schedule a detour to Leica, NJ the next time I'm traveling North from Pennsylvania.

[adan]

3 hours ago, brad_k said:

This camera, the silver M6, usually has a Voigtlander 35mm 1.4 mounted to it. And with that lens, it does focus to infinity.

Bear in mind that the C/V 35 f/1.4 version one was known to have focus shift - the point of "best focus" was different at f/1.4 or f/2 or f/2.8 or f/4 (by which point depth of field tended to mask the problem).

The calibration of those lenses could be factory-adjusted (or third-party adjusted) to suit individual users' desires. For correct focus at f/1.4, or at f/2, or at some other intermediate aperture. (Mine was set for f/2.0 - which worked for me, but was just one of several possibilities)

C/V fixed or at least reduced that problem significantly with the version II, introduced in 2019 and marked "II" on the front engraved ring.

Anyway, the point being that that particular lens type is probably not the best standard for testing, assessing or adjusting the rangefinder - many copies likely have non-standard calibrations.

Which leads to the conclusion that it's your M6 that is out of whack.

[brad_k]

I did know that the C/V 35mm f/1.4 V1, which is what I have, has some pretty sever focus shift. Keep in mind that I'm not discussing results, just what I see in the viewfinder.

You are suggesting that Voigtlander had that lens calibrated from the factory such that it would focus past infinity to account for the focus shift? (If so, that would certainly explain things)

[jaapv]

37 minutes ago, Matlock said:

Of course you could have a serious falling out with your trusted repair shop when you turn up with 7 bodies and 22 lenses. 😀

They might welcome the business… you could buy an optical bench yourself

[brad_k]

Oddly enough, it's been my experience lately that the few shops that specialize in Leica repairs may prefer if fewer people sent stuff their way. They seem to be overwhelmed.

[spydrxx]

Just a thought based on my experience and practices. When I've occasionally noticed a discrepancy in viewfinder focusing I try two things before considering sending gear off to Youxin or DAG. I put the camera on a tripod, focus on an object at or beyond optical infinity (minimum of 1000 x lens focal length, ideally the moon or a planet at night) open the back and set the shutter to B with  a cable release attached. I then put a focusing aid (originally ground glass, but then switched to a SLR focusing screen, which I've properly shimmed) on the film rails and examine the image with a loupe. If everything is fine I repeat the process using a measuring tape and focusing on an object at the lens' minimum distance (or near it depending on the lens)....measuring from the film plane mark, not the lens, to the object. In both cases if the viewfinder patch indicated the object in focus and that was confirmed by an examination of the focusing aid image, great. If they both aren't in synch, I've typically found that the viewfinder needs tweaking.  It also gives me an indication of accuracy of the focusing scale for zone focusing. PITA, but it has worked for me for over 40 years and occasionally prompted me to have my eyes examined for a new prescription).

[Matlock]

11 hours ago, jaapv said:

They might welcome the business… you could buy an optical bench yourself

Now that's a thought.😄

[qqphot]

I don't really understand why but once my IIIf and g are adjusted properly to infinity for one of my lenses, they're more or less correct for the others (not a huge set, admittedly.) But put an adapter ring on the M2, and each is off by a bit, and not all the same. The Barnacks have more magnification than the M2 so I'd expect it to be the other way around, I guess. It's probably technically "good enough" anyway, but i do get more reliably dead-on focus with the screwmounts.

[a.noctilux]

3 hours ago, qqphot said:

But put an adapter ring on the M2, and each is off by a bit, and not all the same

Adapter LTM-M rings thickness can be "off", sometimes.

I have some exactly 1.00mm other from 0.95mm (old used) to 1.02mm just talking about good Leitz/Voigtlander ones.

Other binned "cheap units" noname made of soft metal ranging from 1.05 mm to 0.90mm 👎.

 

[Advertisement]

Hallo,

Look here: Leica M