New 50 'lux lens mount too tight for my M7!

[Jimbond]

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I was very excited when I heard that the much sought after new 50mm Summilux-M became suddenly available yesterday at my nearest Leica dealer. Promptly ordered, it arrived in the post today. Great, just in time for Christmas!

 

Imagine my dismay, when I found my brand new lens wouldn't fit onto my M7 body! It just won't turn round enough to click / lock into place. It only rotates about half the turn of my previous lenses. The plastic cover that covers the lens hole turns and fits just perfectly, with a satisfying 'click'. I took it to a local camera shop, which had some old Leica M bodies (M1, 3 and 5) and it fitted just, but very tightly. I imagine these bodies have had a lot more wear than my M7 (now 7 years old).

 

Has anyone else ever had this problem?

 

I'm naturally reluctant to force it. Even if I could, what are the chances that the focussing mechanism might be slightly out?

 

My previous lenses fitted absolutely fine - not too loose or too tight.

 

The lens comes with a signed test certificate. Just what do they test exactly, if they don't test whether the bayonet lens mount fits?

 

Any thoughts, suggestions most welcome. I really don't want to have to send it back and wait for another to become available.

 

Jim B

Edited December 22, 2010 by Jimbond

[beoon]

Jim,

I got a new 50mm Asph in July after months of searching.

When it was delivered one of the screws on the outer barrel had sharp edges on it (possibly due to over tightening).

Leica UK and the dealer did not have another lens in stock so back it went to Solms for about 6 weeks, it is now perfect and it is a super lens, worth putting up with a small delay to get it perfect.

Regarding the issue with your own lens, I bought a new 28mm lens in the 1990's and it was a very tight fit on my M6, but on my friends M6 it was fine.

It was sent back to Leica UK and it came back sorted, I do not know if they changed the bayonet mount, but these are expensive lenses and you want them to be perfect.

Contact Leica service in Solms and get it fixed, the small delay is worth putting up with for such a fantastic lens.

I actually returned mine via Leica in Mayfair London and also sent a 90mm lens with it to be 6 bit coded at the same time.

 

Alan

Edited December 22, 2010 by beoon
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[scsambrook]

This must be annoying, to say the least. The more usual observation is that it's the digital Ms which have 'tight' bayonets where lenses are harder to mount, which was my own experience. When I got my M8 three of my older lenses went on very firmly though smoothly, but a fourth requires some decided effort to make it lock home. There has been no change in feel in the 18 months I've been using it.

 

Forcing the lens to seat is, as you recognise, not a good idea and regretfully I think you will need to return it to the supplier.

 

You ask "The lens comes with a signed test certificate. Just what do they test exactly, if they don't test whether the bayonet lens mount fits?" It's a fair question, to which the standard reply in these columns will likely be "a standard body at Solms" and your riposte probably "Well, it won't fit mine even though other lenses do". Sadly, something is amiss but you're unlikely ever to find out what or how it came about. I hope you can get a replacement quickly, or at least a full refund.

[hoppyman]

Jim if the lens fits (albeit firmly) on other M bodies you may just have a body and lens that together have too tight tolerances.

What a shame the forum doesn't give us the ability to pass a lens around amongst a bunch of users!

 

The issue is not necessarily wear state, in fact enough wear to make the fit too loose is very unlikely in my experience. I have had two 45+ year old M3's that were firm with every M lens. The key here is how smooth the fit is. Anything even slightly gritty feeling could be an indication of a problem. Any metal edge imperfections, a burr or foreign matter for example? Are all of the flange mounting screws flush or below the surface? You should not see any issues at all in a new lens of course. You do need to be able to turn the lens smoothly until it locks and not have to use undue force.

 

Only you can decide what is acceptable for you, naturally. A firm fit is a good thing but you have to be comfortable. I would ask my dealer for a detailed opinion. Of course you may opt to contact Customer Service and send body and lens together if you are still dis-satisfied. I don't know if you have had any maintenace on your 7 year old M7? If you were getting a CLA your lens could be checked with it too. Is the mount on your camera smooth and clean with no detectable imperfections (scratches, foreign matter, grease)?

 

Finally the firm fit does not imply any focus issue at all. Quite the opposite, if you can feel movement with any lens when it is engaged something is wrong.

Edited December 22, 2010 by hoppyman

[Jimbond]

Thank you all for your comments! I must say it's a little concerning if there is enough latitude in Leica's tolerance range to cause a functional problem.

 

The lens simply won't engage or stay on the camera, so it has to go back. I just hope they can repair it quickly.

 

Please forgive my ignorance, Geoff, but what is a 'CLA'?

 

And no, there is no gritty feeling, grinding etc.

 

Jim

[earleygallery]

What about trying a very very slight smear of vaseline on the mount?

 

Don't forget that every Leica mount is whittled by hand from a solid block of brass, by an octogenarian gnome who works purely by sight and feel using one of Oscar Barnacks original chisels.

[hoppyman]

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James, no that is not recommended. Better not to introduce an uncontrolled sticky lubricant onto the surface of the mount and brand new lens flange.

Jim, Clean, Lubricate and Adjust is commonly used for preventative maintenance (as opposed to repair of a fault).

Regarding tolerances, as I mentioned, without handling your lens personally this is just thoughts of possible factors (AKA speculation!), nothing definitive.

 

That applies to every bit of opinion/advice you read in on-line forums.

But Leica Camera has been making many tens of thousands of camera and lenses with the mount unchanged for more than fifty years. It is certainly possible to encounter variations in mechanical tolerances with any machined parts.

 

What is known is that current tolerances for assembly and manufacture of lenses and bodies are closer than ever before. That driven by the need for closest to perfect as can be achieved for critical focus with the m8 and now more so the M9.

 

Now you are describing not being able to turn the lens until it engages at all. That sounds worse than your original remarks. I'll just repeat my suggestion to talk this through with your dealer. Try his lenses on your camera and vice versa. Talk to Customer Service in Solms too. IF it requires adjustment they ought to be able to turn your lens around quickly for you. After the holiday period?

Returning your very hard to obtain lens and waiting for a replacement may or may not solve your problem and of course could involve considerable delay.

Best of luck to you getting this sorted out to your satisfaction as quickly as possible.

Edited December 23, 2010 by hoppyman

[giordano]

James, no that is not recommended.

 

It is, actually, in the little manual that comes with each M lens (at least the lenses whose manuals I have).

[masjah]

It is, actually, in the little manual that comes with each M lens (at least the lenses whose manuals I have).

 

That is correct. But Leica caution strongly against excessive quantity, and imply that it should be needed only after considerable time (years?), or if the old stuff has been removed by degreasing. A new lens shouldn't need it. In any case though, if a lens won't mount at all, I would have thought that the degree of "mistolerance" would be way beyond what could be remedied by a bit of lubricant.

[hoppyman]

Ok John. I opened one of the instructon booklets from my lenses and it does say that.

To provide the full quote, it also says that the lens has been coated with a thin layer of grease at the factory. Normally this lubricating film will remain on the lens for years, even if the lens is wiped from time to time. In the event that a grease solvent is used when cleaning, a fresh layer of grease should be applied. To do this, apply a small amount of vaseline to the bayonet with your finger and spread it with a clean cloth

Attention! Do not apply too much vaseline to the bayonet!

 

So I mis-spoke . I should have said I personally do not recommend that you apply vaseline to the bayonet flange of a new lens that you consider is too firm to rotate into engagement.

 

Of course I suggested that the OP talk with their dealer for an opinion and that any forum advice was suggestion ( and no substitute for having a hands on opinion from someone competent)..

I was concerned that too much sticky lubricant could get onto the wrong surfaces or retain foreign particles. The key is in a small amount, which I can see that you (and Leica Camera) have suggested if needed. Wouldn't be my personal choice for the job!

[wlaidlaw]

I would recommend silicone grease with micronised teflon rather than vaseline. It does not oxidise and has much better lubricity than vaseline. My MATE lens was very tight after having the mount replaced at Solms. I put a tiny smear of the silicone grease on, after having cleaned the mount with IPA. It mounted with less force after this. The amount you apply must be so small that you can barely see it. Available from Maplins here: Silicone Grease with PTFE : Lubricants : Maplin

I use this stuff for all sorts of applications and would not be without it. More useful than WD40!

 

Wilson

[jaapv]

I second Wilson's recommendation, but note that leica advises vaseline. In any case, if the mount is too tight, the remedy, another mount, is exceedingly simple and quick, provided it is in stock.

[wizard]

Jim, does your new lens just feel tighter and tighter when rotating it to fully mount, or do you feel a sudden stop, as if the lens mount engages something which prevents any further rotation? If it is the latter scenario, then do NOT apply any grease, as this will not help at all.

 

Andy

[earleygallery]

Thanks for validating my information!

 

My thinking was that perhaps for whatever reason there was no grease on the mount. Who knows, maybe the lens was opened at some point and then cleaned spotless with a cloth to repackage it, unknowingly wiping off the grease at the same time. Or the grease bench at Leica missed this one. Anything is possible.

 

If the lens is turning but just tight, then it can't harm to try. As I said a VERY VERY LITTLE smear of the stuff. If that doesn't work then yes, return to sender.

[Jimbond]

GOOD NEWS, EVERYONE!

 

I decided to get it checked out by a camera repair shop in Edinburgh, (the excellent Cameratiks), rather than send it back. Patrick, the man who knows about Leicas there, was back today and confirmed that the body fitted fine with other Leica M lenses, just not this one. Apparently, the lower lens mount flange was for some reason not picking up the spring clip on my M7, so it wouldn't turn any further. He tweaked this spring clip slightly and it all works perfectly now!

 

But yes, in answer to Andy's question below, on reflection, the latter symptoms (i.e. more of a sudden stop at half a turn, not just gradual tightening).

 

Anyway, big PHEW all round! Many thanks for all your helpful suggestions!

 

I now have half a roll of seasonal shots from a frozen but festive Edinburgh Farmers' Market in the can to look forward to.

 

Yours aye,

 

Jim

 

 

Jim, does your new lens just feel tighter and tighter when rotating it to fully mount, or do you feel a sudden stop, as if the lens mount engages something which prevents any further rotation? If it is the latter scenario, then do NOT apply any grease, as this will not help at all.

 

Andy

[jaapv]

All's well that ends well..

[ho_co]

Jaap, should a note in regard to the mechanics of the M mount go into the FAQ?

 

I don't know how one would word it; the OP here at first thought the mount was too tight.

 

We seem to be seeing a number of questions like this as people come back to Leica. Some of the familiar brand-knowledge seems to have got lost in the meantime.

[LeicaPassion]

Jaap, should a note in regard to the mechanics of the M mount go into the FAQ?

 

I don't know how one would word it; the OP here at first thought the mount was too tight.

 

We seem to be seeing a number of questions like this as people come back to Leica. Some of the familiar brand-knowledge seems to have got lost in the meantime.

 

Great news that the problem has been solved. My 50 lux just arrived and it fits like a glove.