6-bit coding and Auto Lens Detection

[UliWer]

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3 hours ago, beewee said:

There’s no mechanical mechanism on the SL bodies to check frame lines but it does support 6-bit coding via the M mount adapter.

Does the M-mount adapter for the SL trigger the right data for the lens automatically or do you have to enter them using the menue?

[UliWer]

3 hours ago, Knightspirit said:

I have a Zeiss 18mm coded for 18mm - but the flange triggers the 50mm frame line. It still shows as 18mm in the file, the frame lines don't seem to matter.

Try with the frame selector in the position which show the framelines for 28/90mm. What do you see in the EXIF?

[AZach]

42 minutes ago, UliWer said:

Does the M-mount adapter for the SL trigger the right data for the lens automatically or do you have to enter them using the menue?

When mounting the 6-bit M-lens is recognized, for any other you can choose focal length from list. (SL2–S)

[UliWer]

44 minutes ago, AZach said:

When mounting the 6-bit M-lens is recognized,

I havn't seen an M-to-L-Adapter from Leica, though I am rather sure it has an interior mechanism which substitutes the functions of the frameline selector. 

[jdlaing]

20 hours ago, lct said:

For Auto Lens Detection, does the M11 take into account:
• (a) the lens code?
• (b) the framelines?
• (c) both of them?
• (d) If both of them, which the M11 gives priority?
I would vote for the framelines but i'm not sure of that.

Both framelines and 6 bit codes.

[beewee]

On 9/15/2025 at 4:37 AM, UliWer said:

I havn't seen an M-to-L-Adapter from Leica, though I am rather sure it has an interior mechanism which substitutes the functions of the frameline selector. 

I took a very close look at my Leica M-L adapter and I can’t see anything that would suggest there’s a something to detect frameline selector position on the adapter.

[jdlaing]

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8 hours ago, beewee said:

I took a very close look at my Leica M-L adapter and I can’t see anything that would suggest there’s a something to detect frameline selector position on the adapter.

The framelines are selected mechanically by the lens. That’s how the camera knows what lens is mounted.

Edited September 26 by jdlaing

[beewee]

12 hours ago, jdlaing said:

The framelines are selected mechanically by the lens. That’s how the camera knows what lens is mounted.

Yes, and there’s no equivalent mechanism on the adapter. Meaning no moving part that could be connected to an encoder, or contact switch, or optical measurement to do information the adapter of the frame line information based on the M-mount flange geometry.

[jdlaing]

12 hours ago, beewee said:

Yes, and there’s no equivalent mechanism on the adapter. Meaning no moving part that could be connected to an encoder, or contact switch, or optical measurement to do information the adapter of the frame line information based on the M-mount flange geometry.

Why would you use an M Adapter L?

Edited September 27 by jdlaing

[beewee]

4 hours ago, jdlaing said:

Why would you use an M Adapter L?

Because I also own an SL3.

[charlesphoto99]

16 hours ago, beewee said:

Yes, and there’s no equivalent mechanism on the adapter. Meaning no moving part that could be connected to an encoder, or contact switch, or optical measurement to do information the adapter of the frame line information based on the M-mount flange geometry.

There are no frame lines to be activated on an L mount camera so no need. The six bit code will relay to the camera the model of lens it is. 

[jaapv]

The MATE needs the mechanical connection, so will not function optimally on the adapter. But that is the only exception. 

[jdlaing]

1 hour ago, beewee said:

Because I also own an SL3.

I understand. What do frame lines have to do with SL cameras? An M Adapter L doesn’t pull up frame lines because there aren’t any.

[jdlaing]

17 minutes ago, jaapv said:

The MATE needs the mechanical connection, so will not function optimally on the adapter. But that is the only exception. 

I don’t think so. 

[jaapv]

For the optical corrections it does. Obviously not for framelines on an adapter.  I guess Leica implemented some kind of average for the lens.

[misteracng]

I have the leica M-L adapter with the SL2s, when using the MATE, it recognizes the lens, but brings up all 3 focal lengths and you have to select which one you are using. If you change the focal length on the lens the camera will not know. You go back into the lens menu and pick one of the other 2 focal length profiles for the MATE

[jaapv]

That is another option, technically more precise, but less user-friendly. Typically Leica. 

[lct]

Unsure how it could work otherwise if there is one code only for the MATE. Just asking as my MATE is not 6-bit coded.

[misteracng]

The MATE on the M11 does change the lens detection automatically. As you change the focal length the camera will change the focal length, based on the rangefinder frameline lever position and the 6 bit code. Of course on the M-L adapter, on the SL series the lens is recognized as a MATE but you have to choose which on of the 3 focal lengths you are using because there is no frame line level to tell the camera.

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[lct]

2 hours ago, misteracng said:

The MATE on the M11 does change the lens detection automatically. As you change the focal length the camera will change the focal length, based on the rangefinder frameline lever position and the 6 bit code. Of course on the M-L adapter, on the SL series the lens is recognized as a MATE but you have to choose which on of the 3 focal lengths you are using because there is no frame line level to tell the camera.

Interesting thank you, but i don't understand.
• In auto detection mode, with my uncoded MATE, the M11 says "Uncoded" and exif data say "Focal Length: 0.0 mm" at the 3 lever positions.
• In manual detection mode, the M11 prompts to choose 28mm, 35mm or 50mm. So, when choosing 50mm for instance, the camera says "4/50mm" and exif data say "Focal Length: 50.0 mm" at the 3 lever positions.
• Therefore, in both auto and manual detection modes, the lever positions play no role at all on lens recognition. What i don't understand is how the same lever positions can have suddenly a role on lens recognition when the lens is 6-bit coded, given that there is one code only painted on the flange of the lens.

Edited September 29 by lct