SL2's software correction of M lenses?

[Chaemono]

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vor 1 Stunde schrieb scott kirkpatrick:

Here's a source of confusion.  I didn't realize that the CL, the SL and the SL2 put different opcodes into the output DNG.  This may change as the SL2 firmware gets brought up to the state that the product team eventually wants to reach, but at present the SL2 only generates distortion corrections for the L-mount zooms but prints default values for M lenses and the Summicrons, which have no effect.

Here's what the WarpRectilinear opcode actually contains in a file made with a CL using the CL35 Summilux.  The following lines were extracted from the DNG file:

<<<<

LensSpecificationExif: 35.0 mm f/1.0

*** Warning: Exif IFD LensMakeExif is not NULL terminated ***

LensMakeExif: "LEICA CAMERA AG"

LensModelExif: "Summilux-TL 1:1.4/35 ASPH."

 

Opcode: WarpRectilinear, minVersion = 1.3.0.0, flags = 0

Planes: 3

  Optical center:

    h = 0.500000

    v = 0.500000

  Plane 0:

    Radial params:     1.000710, -0.015868, 0.004349, 0.001293

    Tangential params: 0.000000, 0.000000

  Plane 1:

    Radial params:     1.000077, -0.015829, 0.004921, 0.000961

    Tangential params: 0.000000, 0.000000

  Plane 2:

    Radial params:     0.999930, -0.015013, 0.004551, 0.001189

    Tangential params: 0.000000, 0.000000

>>>>

The only lines that really matter are the three lines, one for each color "plane" labelled Radial Params.  If they were 1 0 0 0 that describes having no distortion, and needing no correction.  These coefficients are pretty small, and the differences between them (the LCA correction) are even smaller (around a per cent). 

Here are the opcodes (I took out more of the irrelevant stuff) for the M 21 Super-Elmar 21, shot on a CL:

<<<<

21 SE3.4 in an M to L Leica adapter:

LensSpecificationExif: 21.0 mm f/3.5

LensModelExif: "Super-Elmar-M 1:3.4/21 ASPH."

Opcode: WarpRectilinear, minVersion = 1.3.0.0, flags = 0

Planes: 3

  Plane 0:

    Radial params:     1.000403, -0.023597, 0.011575, -0.000911

  Plane 1:

    Radial params:     1.000048, -0.023363, 0.011650, -0.000956

  Plane 2:

    Radial params:     0.999815, -0.022986, 0.011723, -0.001012

>>>>

Those  params would be replaced by 1 0 0 0's in the SL2's output at present.

Note_  the SL's also puts this information in, but the numbers are different because the sensor is bigger.

Thanks.  Really geeky stuff but somebody’s got to do it. 😁

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[scott kirkpatrick]

8 hours ago, Chaemono said:

And it’s baked into the RAWs, not corrected by opcodes. As stated earlier, there aren’t any opcodes with SL2 files when using M lenses. 

I suspect that this will change, as the CL and SL do insert corrections for some lenses where the SL2 at present does not.  When I look at, for example, a CL file for the M21 SE in Capture One and set the profile dialog to show the distortion correction that is coded into a CL file, the black region around the corrected file is only a few percent of the width of the frame.

Tailwagger above talks about giving an M lens a slight twist so that its 6-bit code is not read and thus the lens is unrecognized.  That does much more than just removing the distortion/LCA opcodes.  It also eliminates whatever color shift correction at the edges and vignetting correction that the camera might have intended to apply, And if Adobe has some secret sauce that it will use when the lens is recognized, and you use LR, that's gone as well.  It used to be possible in the Ms to turn off lens recognition.  Is that not possible in an L-mount camera?  My SL and SL2 sometimes remind me that they have just identified an M lens, and sometimes don't say anything.  I haven't figured out the protcol, but so far they almost always know what is mounted.  I have fooled the SL2 just once, changing an M lens and not having it recognized, but that didn't seem to be reproducible.

[Tailwagger]

2 hours ago, scott kirkpatrick said:

My SL and SL2 sometimes remind me that they have just identified an M lens, and sometimes don't say anything.  I haven't figured out the protcol, but so far they almost always know what is mounted.  I have fooled the SL2 just once, changing an M lens and not having it recognized, but that didn't seem to be reproducible.

This largely mirrors my experience as well.  On a couple of occasions, with an M lens mounted the camera menu pops up, sits there and waits for a reply. Most often, it pops up for a brief second, then just disappears and sets the lens without any interaction (per the exif). Still others, no menu popup, but the lens gets set.  At first I thought that perhaps I inadvertently had a finger on a button, but I repeated things and found that I didn't. It occurs to me now that perhaps the opposite is true; ie. have your thumb on the menu, func or play button as you turn the camera on, seems not a hard thing to do,  and the behavior changes. I don't recall reading anything like that in the menu, but software often has its easter eggs and its not an unusual technique to change behavior when a button or combo of buttons are held on startup. Dunno. 

[scott kirkpatrick]

The other odd behavior with M lenses is that at times I have found IBIS off and that menu item greyed out.  Does anyone know what causes that?

[caissa]

1 hour ago, scott kirkpatrick said:

The other odd behavior with M lenses is that at times I have found IBIS off and that menu item greyed out.  Does anyone know what causes that?

The missing focal length.   (When no lens is recognized.)
I would like to get the option only to add the focal length, and not selecting a lens (as I am using also foreign lenses). As implemented on the S1R.

Edited January 19, 2020 by caissa

[scott kirkpatrick]

But the EXIF was correct on those shots.  I tried switching off and then on again without waking up the IBIS.  I'll have to see if it happens again and do a more careful diagnosis.

[caissa]

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It will be interesting, if the first firmware update will improve the SL2 to the level of the SL.  (Had actually expected that from the beginning...)

[bags27]

Did you try to uncouple the lens from the camera + adaptor and then recouple?

Edited January 19, 2020 by bags27

[scott kirkpatrick]

6 hours ago, caissa said:

It will be interesting, if the first firmware update will improve the SL2 to the level of the SL.  (Had actually expected that from the beginning...)

The SL2 is in some ways ahead of the SL.  The SL could either automatically identify a lens or let you choose from a list of M or R lenses (the list it offered depended on which Leica adapter you used.  The SL2 also offers (as do the Ms) the option to turn lens recognition OFF.  Once you do that on the SL2, IBIS also goes off, as I haven't found a way to put a focal length in when the lens isn't recognized or selected from the list.  

[caissa]

I was referring to your entry 22. And would have hoped that the corrections added by the SL would have been included by SL2 as well.

”where the SL2 does not” is what you said. Did I interpret it incorrectly ? (Is this better ?)

Edited January 19, 2020 by caissa

[caissa]

Another problem. There are R zooms that always show the current focal length in use. Others do not. And all zooms adapted mechanically do not (also the WATE and MATE). How to set IBIS in this case ?  For the middle of the range ? With a number, no problem, with selecting a lens a strange procedure. And if you wanted to set the correct focal length manually ? Only feasible with a number, not with selection of a lens.

On the SL it was no problem, it could simply be ignored. But on the SL2 I don’t want to lose IBIS, so ignoration is a losing strategy. (In this sense, how is the SL2 ahead ? )

[Leicaiste]

12 minutes ago, caissa said:

Another problem. There are R zooms that always show the current focal length in use. Others do not. And all zooms adapted mechanically do not (also the WATE and MATE). How to set IBIS in this case ?

 

[caissa]

Sorry, no solution. What helged replied is exactly the right answer.  Should be easy to implement.

Edited January 20, 2020 by caissa

[Leicaiste]

For the time being it is the only solution. 

And to choose a focal length in a list or a menu may not be faster. 

Anyway we will see what the next firmware will offer. 

[scott kirkpatrick]

18 hours ago, scott kirkpatrick said:

The SL2 is in some ways ahead of the SL.  The SL could either automatically identify a lens or let you choose from a list of M or R lenses (the list it offered depended on which Leica adapter you used.  The SL2 also offers (as do the Ms) the option to turn lens recognition OFF.  Once you do that on the SL2, IBIS also goes off, as I haven't found a way to put a focal length in when the lens isn't recognized or selected from the list.  

Oops again --  when I looked into the menus of an actual SL, rather than the original manual, I found an OFF option in the lens profile section.  Maybe it came in when there was a big firmware upgrade around release 3.x. 

I'm having a conversation with Leica Customer Care about what happened to the distortion/LCA corrections in the SL2.  I'll pass along whatever I learn.