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Found the lens decoder table in 1.09 firmware


scott kirkpatrick

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It starts at location 38B6 (hex). In Notepad, look for the string "uncoded" which we know is the binary 000000.

 

The table looks like this when lined up carefully in Notepad (I took a screen shot):

 

decodetbl.jpg

 

Carsten, how does this compare with your table? You can see the max aperture, focal length and product codes. The little symbols that look like a backwards "r" (call it "left), an "L" (call that one "center") and an "r" (call it "right") indicate the matching frame lever setting, and relate to the lens listed on the immediately following line. The various symbols in between can be read off with hex editor, but I haven't tried to interpret them.

 

scott

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Peter,

 

I think you are talking about 1.10 which has not been released yet. 1.09 is what Leica has been installing on the hardware fixed cameras for awhile.

 

Best,

 

Ray

 

 

(oops!!! You posted, while I was typing and watching the finish of the race.)

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Scott, someone (was it Carl Brevette?) played with the firmware in a hex editor once, which is how this table got completed. I am missing the funky little symbols on the right though :) I suppose that must be the encoded corrections to the lenses.

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Scott, someone (was it Carl Bretteville?) played with the firmware in a hex editor once, which is how this table got completed. I am missing the funky little symbols on the right though :) I suppose that must be the encoded corrections to the lenses.

 

Once I compared your table with the code, I realized that you had more cases listed than there were pictures, and figured that this was not such new news. The list of frame indications seems complete, but in practice sometimes lens detection depends on the frame lines and sometimes not. I wonder how that could be so buggy? And I haven't figured out what is going on around the two TEs. The little squiggles are probably pointers to some list of possible actions to take for each lens. There may be some patterns, like what do all the Z's do?

 

scott

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About the inconsistency with framelines, it may just be that Leica didn't care what was in the empty fields? It doesn't make much sense, I admit, but neither does the status quo.

 

At some point I will probably take a look in a hex editor and see what I can find. I would expect that the "squiggles" are either floats or doubles, and represent correction coefficients of some kind. Maybe by comparing lenses with strong vignetting with those with little vignetting, we can make intelligent guesses as to what is what.

 

Carl, sorry for butchering your last name. I thought I had it right, but should have checked.

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Carsten,

I'm used to people being creative with my family name :D. As for the other data in the tables. I think we'll see some of the data being coded in "rational" format. Thats a data type used extesively within EXIF/TIFF (and thus also DNG) tags. I've been looking at the table briefly, but haven't been able to verify anything yet. My supply of M8 files is too limited to be able to cross refference the data in the FW table with the EXIF data in the DNGs. I'll get there, but it might be a while longer.

 

- Carl

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There may be some patterns, like what do all the Z's do?

Apparently the lens info is stored before, not after the strings. For example, hexadecimal "5A" ist ASCII-Z, but in decimal it’s 90 – and there’s a "Z" in front of all 90 mm lenses. If you check the values for the other lenses, it will always correspond to the focal length. I haven’t figured out the TEs, though.

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If you're refering to the value that is located 28 bytes before the start of the lens name, it looks to me as if this number is an index of some sorts. It increases by four for each element in the table.

 

One tidbit on the TE/WATE: For the TE, the three focal lengts are in three longs starting at 17 bytes before the start of the lens name. For the WATE (as well as the other lenses) these table elemens are zero. For the TE the focal length indicator at 24 bytes before the lens name is zero, for the WATE this is zero too.

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