Wide Lenses Won't Mount on an M6 Body?

[j. white]

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I just got a "new" M6 TTL body - an LHSA black paint model in pristine condition. Let me just say that I am thrilled with it, except for one detail: neither my MATE nor Summicron 35 ASPH will mount on the body. They turn about 1/8 of the way before locking and just stop up. No troubles with the Summicron 50, nor the Elmarit 90 and all of them mount just fine on my 1st M6 TTL. A visual comparison between the two bodies shows no major differences in their mounts/mechanisms.

 

Has anyone encountered this phenomenon? Since this was a find on a discontinued model, a return is unlikely.

 

Any suggestions welcome!

 

 

-J.

[doubice]

I have neve heard of this but, it sounds like something is blocking the lenses inside the film chamber and preventing them for seating fully.

 

I would suggest the following: open the film door and while holding it open, fire the shutter at 'B' (use a locking cable release to keep the shutter open). With the shutter open, try mounting the offending lenses and observe from the back of the camera if there is anything in the lens' way.

 

This will obviously not fix it but, it might shed some light on what the problem may be.

 

Best,

 

Jan

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[leitz_not_leica]

Not in the film chamber, but something to do with the lens mounts with the two non-mounting lenses...bent?

[spydrxx]

If the lenses mount fine on another body, then it sounds like your "mint" M6 needs a trip to the camera doctor.

[Tom Johnston]

I've had only one experience with a lens not staying locked into place on my M6. That was with a 50 Summilux. When it first happened, I was focusing and the lens just came loose in my hand. I thought that I was lucky, since I was indoors, and a close call. Paying attention and trying to figure it out, I found it did lock into place with a click, but it just wouldn't stay locked. None of my other lenses had ever done this, either on this body or my M3 or M4, and I had previously had an older 50 Summilux which was fine.

The dealer suggested sending the body and lens to Leica, but, as mentioned above, no problems with any other lenses, I opted to just return the lens...well, since I had already paid for it, I just used that credit toward my M7.

That Summilux is one beautiful lens...but I make do with my Summicrons.

[j. white]

Wow, it is great to have this resource, especially for those of us using "outdated" gear.

 

Jan & Steve,

 

Thanks for the tips - while you're right that I can't fix the problem, I have a better idea of whats going on. It does appear that flanges are stopping on the frame selector mechanism. Comparing the lenses shows nothing bent or out of alignment with the those on the 35 and MATE.

 

Steve,

 

Yes, a trip to the doctor is the obvious, if unfortunate answer.

 

And Tom,

 

This is a little different than your case since the lenses won't lock in place at all, but based on yours and the lack of any other responses, this does seem to be a pretty rare occurence.

 

Many thanks!

 

 

-J.

[earleygallery]

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Just a thought, the lens mounts and camera mount should have a light covering of grease (very light). I wonder if yours have been cleaned too enthusiastically?

[j. white]

Thanks James,

 

Adding a light coating of Vaseline (I imagine lighter than Leica's post-cleaning recommendations) hasn't made the 35 come clean so-to-speak. The MATE returned from a CLA at the Solms Spa less than two months ago, so I doubt it would benefit from further application.

 

It looks like a trip to the doctor and a call to my dealer's customer support line are in order here folks.

 

 

-J.

[doubice]

I've had only one experience with a lens not staying locked into place on my M6. That was with a 50 Summilux. When it first happened, I was focusing and the lens just came loose in my hand. I thought that I was lucky, since I was indoors, and a close call. Paying attention and trying to figure it out, I found it did lock into place with a click, but it just wouldn't stay locked. None of my other lenses had ever done this, either on this body or my M3 or M4, and I had previously had an older 50 Summilux which was fine.

The dealer suggested sending the body and lens to Leica, but, as mentioned above, no problems with any other lenses......

 

 

This is a phenomena that can occur when manufacturer's extreme plus and minus tolerances meet on mating surfaces. The camera's lens lock was probably at the end of the 'plus' tolerance and the Summilux's locking recess was the extreme 'minus' side.

 

Simply put, the camera's locking pin is fractionally larger than the lens' locking recess. You might get the 'click', but the pin does not seat itself fully in the lens.

 

Happens more often on equipment with very tight manufacturing tolerances. I have a Telyt 4.8/280 which would not stay locked on a Visoflex III; after some pondering and fidling with a micrometer, I found that the mount on my 2.8/135mm Elmarit M was an identical design and thickness to the Telyt. I switched the mounts and presto - both lenses locked correctly - the Elmarit to the M body, the Telyt to the Visoflex. I even tried mounting the Elmarit directly to the Visoflex and the 280mm Telyt to the M body - both locked fine. Lesson - the Visoflex and the Telyt were at the extremes of their tolerances and thus would not lock. Once a part with a different manufacturing tolerance was brought into it, all fit well.

 

I could have also removed the Visoflex's locking pin and filed it a fraction of a milimeter narrower; in retrospect that would have fixed the problem too.

 

Best,

 

Jan

[marknorton]

Check that the frame selection lever, visible just behind the mound on the right hand side (viewed from the front of the camera moves when you use the pre-view lever. If this was seized, it would prevent certain lenses mounting.

[j. white]

Check that the frame selection lever, visible just behind the mound on the right hand side (viewed from the front of the camera moves when you use the pre-view lever. If this was seized, it would prevent certain lenses mounting.

 

Thanks, Mark - that makes a lot of sense. The frame lever is functioning just as the one in the other body does, however its alignment relative to the bayonet spring is ever so slightly different. Jan's astute comments regarding tolerances may well be the culprit. (Here's hoping it's nothing more serious than an alignment issue.) I am also reminded that prior to coding and a recent repair, the MATE didn't fit on my Visoflex bellows either - the mount was simply too tight to engage the flanges on the lens at all.

[doubice]

......... the MATE didn't fit on my Visoflex bellows either - the mount was simply too tight to engage the flanges on the lens at all.

 

The mounts on bellows and on the Visoflex are not as complex as the ones on the camera bodies. The bodies have springs which compress and hold the lenses in place. The Visoflex and bellows mounts use 'wings' (for a lack of better expression), which compress when lenses are mounted. Depending on the positioning of those 'wings', lenses can be mounted with more or less force having to be applied. If you remove the front mount from the bellows, you will be able to compress the 'wings' and thus adjust the amount of force nedded to lock the lens in place.

 

Again - could be the tolerance issue described earlier.

 

Best,

 

Jan

[doubice]

Just another thought on the original mounting problem….. The 35mm Summicron does not really activate the frame lines as the 35mm/135mm frame is the default. 28mm, 50mm, 90mm and the WATE have one bayonet lug longer to push the frame selector onto position.

 

This would indicate that the problem might not be the frame selector, since the 35mm lens does not actually have to move it. The MATE will move the lever, if set to 28mm or 50mm. The 28mm position should move the lever all the way towards the lens, in the 50mm setting the lever should stay in a vertical position.

 

When mounting the ‘unmountable’ lenses, do they come to a solid stop or, do you feel that the lens could be moved further if more force was applied? I would try to mount the 35mm ‘cron using the method I described above (with the shutter and back door open) and use more force. Observe from the back what happens - if there is no visible obstruction, try to force the lens into place. Of course use ‘common sense force’, observing what is happening from the back.

 

Just a thought……

 

Jan

[j. white]

The 35mm Summicron does not really activate the frame lines as the 35mm/135mm frame is the default. 28mm, 50mm, 90mm and the WATE have one bayonet lug longer to push the frame selector onto position.

 

When mounting the ‘unmountable’ lenses, do they come to a solid stop or, do you feel that the lens could be moved further if more force was applied? I would try to mount the 35mm ‘cron using the method I described above (with the shutter and back door open) and use more force.

 

These are keen observations - I noticed this when I intially tried mounting the lenses with the back & shutter opened. The 35 Summicron definitely stops cold, but there is some play with the MATE. I tried forcing it as far as common sense would allow (my father's voice yelling at me to "never force anything!" playing in the back of my mind - ha ha) but it too reaches a point where I could no longer continue for fear of creating an even bigger problem.

[Alberti]

I go for the grease suggestion, if I may call it so. I had some problems in getting the L39/bajonet adapter in place on the body.

So after reading the manual, I added a little vaseline on the sliding parts and do not habitually clean the mount with my finger (what I have been doing for 30 years on my M2 and M6).

 

As well I filed a bit from the (just the edges) from the adapter. This because they were by touch a bit sharp. After that the Other Lens now can be mounted good.

It told me that just buying cheapo components is not the best to get all quality. It also initially made me afraid of little metal parts (tear and wear from these badly made parts from non-Leica adapters) landing in the light chamber.