6-bit coding and Auto Lens Detection

[lct]

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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.

[Carlos cruz]

I believe that those are two sovereign systems- framelines information is transferred mechanically via cut outs in lens bayonette and 8bit system relays info on exact type of lens to meta file. I never ran a test to check what happens with lens info when shooting with frame line preview lever out of designated position. 
(A) is my final answer

[sandro]

I probably don't understand the question. But I have many lenses that I coded myself with Akara Labs code template. The correct lens information shows and the corresponding frame lines appear in the viewfinder. So I get the impression it is connected.

Lex

[Carlos cruz]

A good test to your conundrum would be any goggled lens that has been coded, if framelines would be taken into account all your goggled 35 summicron/luxes would be saved as 50mm picture. 

[jaapv]

47 minutes ago, sandro said:

I probably don't understand the question. But I have many lenses that I coded myself with Akara Labs code template. The correct lens information shows and the corresponding frame lines appear in the viewfinder. So I get the impression it is connected.

Lex

If you push the frameline lever during exposure the focal length will not be recorded when you view the data on the LCD., nor will it appear in EXIF so the focal length is not recorded when there is a discrepancy between the coding and framelines.

[pedaes]

53 minutes ago, jaapv said:

So I get the impression it is connected.

 

Another thread where we are all probably saying the same thing. As @jaapv said, the framelines is a mechanical thing, nothing to do with six-bit coding, as it has always been since M3.

What I didn't know and don't understand is that if you move the frameline lever during an exposure with a six bit lens attached it cancels some EXIF data.

[jaapv]

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It has to do with the MATE, which had to move the framelines and change EXIF at the same time.  

[lct]

1 hour ago, jaapv said:

If you push the frameline lever during exposure the focal length will not be recorded when you view the data on the LCD., nor will it appear in EXIF

True with some lenses, but not with others, strangely enough.

[jaapv]

It does not work this way with manual selection.

[lct]

6 minutes ago, jaapv said:

It does not work this way with manual selection.

I mean in Auto Lens Detection, hence my question.

[lct]

Just tried with 3 Summilux lenses coded by Leica.
• With a Summilux 35/1.4 FLE v1, however i set the frame selector, exif data say "Summilux-M 1:1.4/35 ASPH", so priority to lens code in this example.
• Different experience with a Summilux 50/1.4 FLE v1. With 50/75 and 35/135 framelines, exif say "Summilux-M 1:1.4/50 ASPH". But with 28/90 framelines, exif say "R-Adapter M".
• Similar result with a Summilux 50/1.4 v3. With 50/75 and 35/135 framelines, exif say "Summilux-M 1:1.4/50". But with 28/90 framelines, exif data say again "R-Adapter M". Unsure where the error comes from but framelines have apparently an effect on Auto Lens Detection.

[UliWer]

I think the so-called "6-bit-code" is an "8-bit-code" in reality. It consists of the 6 bits read by the sensor on the camera's flange and the position of the frameline selector. The later can either be "1" or "0". If it is "0" the position of the frameline selector doesn't matter.  

[lct]

The frame selector has 3 positions. So 9 bits actually?

[UliWer]

Electronic devices can only understand binary codes: either "1" or "0" - same for the black and white code on the lenses: black is "1" white is "zero". So if the code which triggers the EXIF etc. has a "0" at the position activated by the frameline selector, the selector doesn't matter. Only if the code has a "1" at the relevant position it needs to be activated by the selector. The selector can't have a position "2" as the electronics doesn't understand this.

Your experience with the 50mm Summilux shows this: two positions of the frameline selector show the right data in the EXIF, so both seem to have the meaning "1". The third position seems to have the meaning "0", which triggers wrong data since the camera expects a "1".

I don't know how they do this with the different focal lengthes of the WATE or MATE. 

[jaapv]

The WATE does not differentiate between frameline position as there are no framelines for its focal lengths. It is designed to need only one set of optical corrections, making it behave like a prime lens. The MATE does indeed use the frameline input for the digital pipeline. 

[DadDadDaddyo]

 

58 minutes ago, jaapv said:

The MATE does indeed use the frameline input for the digital pipeline. 

Exactly my impression from the documentation. With a 6 bit encoded MATE, the 6 bit dots tell the camera body it's a MATE, and the frameline selection, entirely mechanical in input, gets read into the EXIF data to record the focal length for each shot. In other words, the mechanical position does indeed get translated into digital metadata. 

[beewee]

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. 

Because of this, at least for now, I don’t expect Leica is using the mechanical frame selection in the bayonet to communicate more information to the M body. The MATE is a bit of a special case.

Edited September 15 by beewee

[Knightspirit]

12 hours ago, jaapv said:

If you push the frameline lever during exposure the focal length will not be recorded when you view the data on the LCD., nor will it appear in EXIF so the focal length is not recorded when there is a discrepancy between the coding and framelines.

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.

[lct]

2 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.

I have no experience with 18mm lenses but framelines could possibly matter if there were a discrepancy between the code (18mm) and another frameline than the expected 50mm i suspect. Happened to me with a LTM 21mm lens. This focal length triggers 28/90 framelines on M mount normally. I tried to pen code the lens as 21/2.8 on a 50/75 LTM  to M adapter. The M11 did not recognize the lens as a 21mm this way but as a 50mm lens instead. The simple fact to use a 28/90 adapter with the exact same code sufficed for the camera to ID the expected 21/2.8 mm lens. I could not tell what effect the framelines happened to have on Auto Detection in this case but it did have some effect apparently.

 

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[elmars]

vor 10 Stunden schrieb lct:

Just tried with 3 Summilux lenses coded by Leica.
• With a Summilux 35/1.4 FLE v1, however i set the frame selector, exif data say "Summilux-M 1:1.4/35 ASPH", so priority to lens code in this example.
• Different experience with a Summilux 50/1.4 FLE v1. With 50/75 and 35/135 framelines, exif say "Summilux-M 1:1.4/50 ASPH". But with 28/90 framelines, exif say "R-Adapter M".
• Similar result with a Summilux 50/1.4 v3. With 50/75 and 35/135 framelines, exif say "Summilux-M 1:1.4/50". But with 28/90 framelines, exif data say again "R-Adapter M". Unsure where the error comes from but framelines have apparently an effect on Auto Lens Detection.

It does indeed appear that the position of the image field selector has an influence on which lens is selected. With my 35 Summilux FLE, this is always displayed in the Exif, regardless of the position of the lever. With my Summilux 50 classic, however, a 35 Summilux is displayed when I move the lever all the way towards the bayonet.