M-10 not recognising my Summicron 35/2

[Khun Hans]

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vor 1 Stunde schrieb adan:

Does your 35mm have the official factory 6-bit coding from Leica? (machined pits filled with black or white paint?)

Does your 35mm actually bring up the 35mm framelines in the viewfinder?

Are you sure the lens is mounting completely and locking into position?

Have you checked both the lens's 6-bit black and white coding pits - and the camera's 6-bit detector plate - to make sure neither are contaminated: grease on the camera detector; or white dust or black grime on the lens coding marks?

When I had the problem on my M10 with 35mm Cron, I went back to the Leica Store in Kyoto Japan where I bought the 35 Cron 2 days before. The technician tried out everything, including your points, to make it work. Finally the store manager decided to take the lens back and replace it by another new one. And now the big surprise, the new one didn't work either.

Every other focal length of the store worked fine. The M 10 did change the framelines correctly at any time.

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[MrQ]

What was interesting for me is the fact that both my Summicron 35/2 and my Chinese made 7Artisans 35/2 M-mount lens (I bought it used for super cheap) which is also 6-bit coded were not auto detected on my M10.   My M240 camera on the other hand detected both with no issue.  All of my other Leica 6-bit coded lenses are detected on the M10 and M240 with no issue either.

Out of curiosity, how does the lens detection sensor on the camera work?  Is it based on light being emitted and reflected back onto it (dark coded slits almost no reflection, white coded slits reflect back?)

Best regards

[adan]

2 hours ago, MrQ said:

Out of curiosity, how does the lens detection sensor on the camera work?  Is it based on light being emitted and reflected back onto it (dark coded slits almost no reflection, white coded slits reflect back?

Exactly - but infrared light (six LED emitters/receivers).

Of note - I use a C/V 35 f/1.4 MC coded as a "35 Summicron v.4," since that is close enough for the very-similar DG optics, and an easy code to produce with a Sharpie pen (000110). And it is read correctly all the time. But I also had a factory-coded 35 cron ASPH (original type) for a while - and that worked too. Still a mystery why some don't.....

Edited December 31, 2019 by adan

[Kwesi]

Sounds like a batch of 35 cron ASPH v2 lenses were coded with paint that is slightly different from the Leica standard. The M10 has the most sensitive 6 bit reader of the digital M's.

Match Technical stopped selling their coding kit after the type 240 which was more sensitive than the M9.

I'm sure there is a 35 cron ASPH v2 serial# range with faulty paint

[adan]

8 minutes ago, Kwesi said:

Sounds like a batch of 35 cron ASPH v2 lenses were coded with paint that is slightly different from the Leica standard. The M10 has the most sensitive 6 bit reader of the digital M's.

1) Sounds possible - and yes, the M10 is more sensitive.

2) Touch 'em up with a Sharpie, then.

[parsod]

3 hours ago, Kwesi said:

Sounds like a batch of 35 cron ASPH v2 lenses were coded with paint that is slightly different from the Leica standard. The M10 has the most sensitive 6 bit reader of the digital M's.

Match Technical stopped selling their coding kit after the type 240 which was more sensitive than the M9.

I'm sure there is a 35 cron ASPH v2 serial# range with faulty paint

Yes, this might be the case. I can't see much difference when it comes to the quality of the paint on my 35 cron compared to the other four Leica lenses which are working. As long as this is the only lens not recognized by my M10 I just have it selected in the manual list which the camera default to when I mount it. This way I don't need to go into the menu when changing lenses. 

[Kwesi]

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Sounds like this has affected enough people that Leica must know about this. My guess is there is no official recall because the problem only appears when this batch of 35/2 ASPH v2 lenses are mounted on an M10 variant camera. That being said, I'm sure Leica is aware of the problem and will happily replace or recode the lens flange at no cost. 

[Khun Hans]

Bought mine in August 2017 long enough ago to correct the thing on newer batches.

[crons]

On 1/1/2020 at 10:11 AM, Khun Hans said:

Bought mine in August 2017 long enough ago to correct the thing on newer batches.

I just bought mine 2 days ago at the leica dealer. Brand new sealed in the box. Same issue. Box says August 2018. 

[mujk]

The tolerances required by the 6-bit coding system are not particularly tight, which makes it possible for users and third parties to code uncoded lenses themselves with fairly high reliability of detection. For some reason Leica managed to make at least one batch of cron 35 v2 lenses with a code that was not within tolerances when mounted on an M10, resulting in a failure to detect the lens. My guess is that this is purely a manufacturing problem and that Leica knows the reason. However, it seems that the problem might not be associated only with this particular lens. At least my M10 occasionally fails to detect my 21 SEM, which is my newest lens, while this never happens with older lenses, including the 35 cron v1.

[crons]

24 minutes ago, mujk said:

The tolerances required by the 6-bit coding system are not particularly tight, which makes it possible for users and third parties to code uncoded lenses themselves with fairly high reliability of detection. For some reason Leica managed to make at least one batch of cron 35 v2 lenses with a code that was not within tolerances when mounted on an M10, resulting in a failure to detect the lens. My guess is that this is purely a manufacturing problem and that Leica knows the reason. However, it seems that the problem might not be associated only with this particular lens. At least my M10 occasionally fails to detect my 21 SEM, which is my newest lens, while this never happens with older lenses, including the 35 cron v1.

Strange. Because when you look at it, to the eye, the coding looks like just any other lens. It's identical to my 50 summicron. 

My 35 v2 is from August 2018. 

Edited June 7, 2024 by crons

[mujk]

2 minutes ago, crons said:

Strange. Because when you look at it, to the eye, the coding looks like just any other lens. It's identical to my 50 summicron. 

My 35 v2 is from August 2018. 

Agree. The differences are probably very subtle but enough to cause a misdetection. I have been looking at my coded lenses and there seems to be minor differences in the spacing between some "code pits" and also in the amount of paint in each pit. But any differences in the (tangential) location of the whole code are hard to detect without proper measuring equipment. For example a difference in viewing angle may indicate a difference that is not there in reality:

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Left top: Cron 35 asph v1

Left bottoe: Elmarit-M 28 asph

Right: SEM 21

And, as already mentioned, my SEM 21 sometimes fails to be detected on the M10, while this never happens with the other two lenses.

 

[crons]

Althoigh it isn't a big issue in use, I guess if I really want to know the answer I would have to take both camera and lens to Leica. Maybe rheyll have to send them both out to Germany. This isn't something I'm willing to do. 

The problem here I found is people buy and sell gear so much the ones who had the issue a few years ago no longer have that gear. So if you ask them they will say that they don't know what happened. They're on to new lenses and cameras now. I keep my gear long. 

[crons]

6 minutes ago, mujk said:

SEM 21 sometimes fails to be detected on the M10,

Will you just keep it as is? I wouldn't notice it on my 35 because I've selected the 35 cron ASPH manually so it switches to it anyway. The lens is perfect and lovely otherwise. Can you choose yours manually? 

Edited June 7, 2024 by crons

[mujk]

Just now, crons said:

Will you just keep it as is? I wouldn't notice it on my 35 because I've selected the 35 cron ASPH manually so it switches to it anyway. The lens is perfect and lovely otherwise. 

Yes, it doesn't happen too often and I have gotten used to checking that this particular lens is detected ok after a change (although sometimes I forget). I have two uncoded lenses in regular use (50 and 90) so the default in case of a detection problem with the SEM 21 will be whichever of these I have used most recently.