Unknown EXIF / converting to DNG

[01maciel]

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I own a M10 and shoot solely DNG raw files. My latest toy is an L-mount camera (S1R) in combination with my M-lenses which creates Panasonic specific RW2 files. When I upload the L-mount RW2 files to my computer I add some M-lens information to EXIF using a simple cli script.
Whether it makes sense or not to convert the RW2 raw files to DNG files and throw the RW2 in the bin afterwards? I don't know- but I am still experimenting with both formats. Adobe provides the proprietary "Digital Negative Converter" (which runs unter Linux/Wine, too) to convert raw files. So far, so good. When I compare EXIF information side-by-side of a RW2 file and the converted DNG it shows lots of differences.
The Lens ID and Lens Model for instance (see table below) were not converted correctly to the DNG file. The tag Rows Per Strip (whatever that means) is converted from 5632 to 171 which is obviously incorrect. And some of the tags does not exist either on the one or the other side, e.g. Gamma, Sensitivity Value or Linear Response Limit.

 

Tag/RW2                         Value/RW2                    Tag/DNG                           Value/DNG
-----------------------------------------------------------------------------------------------------------------------------

Gamma                           : 2.7578125                   <
                                                             > History Action                  : derived, saved
                                                             > History Changed                 : /
                                                             > History Instance ID             : xmp.iid:fbab2b0f-bcfa-e946-
                                                             > History Parameters              : converted from image/x-pana
                                                             > History Software Agent          : Adobe DNG Converter 13.4 (W
                                                             > History When                    : 2021:10:21 12:25:18+02:00
                                                             > Instance ID                     : xmp.iid:fbab2b0f-bcfa-e946-
Lens Attached                   : No                          <
Lens ID                         : Summicron-M 1:2/35 ASPH     | Lens ID                         : 35.0mm
Lens Model                      : Summicron-M 1:2/35 ASPH     | Lens Model                      : 35.0mm
                                                             > Linear Response Limit           : 1
                                                             > Look Name                       :  
                                                             > Metadata Date                   : 2021:10:21 12:25:18+02:00

Rows Per Strip                  : 5632                        | Rows Per Strip                  : 171
                                                             > Scale Factor To 35 mm Equivalent: 4.4
Sensitivity Value               : 4                           <
                                                             > Shadow Scale                    : 1
Shutter Speed Value             : 1/203                       | Shutter Speed Value             : 1/200
Software                        : Ver.1.9                     | Software                        : Adobe DNG Converter 13.4 (W

 

Any ideas or comments on the idea to convert vendor-locked raw files like RW2 to DNG and how to attain the best possible accuracy of EXIF information?

[Anbaric]

I'm not sure it makes sense to convert them to DNG at all, unless you have an old raw converter that can't handle S1R RW2 files. If the DNG converter can read them, then probably any current raw converter can too, so there's no real lock-in. The RW2 format, which is similar to other raw formats, is well understood and can be processed by Open Source tools, so the knowledge of how to read them won't be lost.There may be proprietary tags, but the DNG converter won't do anything useful with them either. DNG conversion is a one-way process (unless you embed the original raw), so if you delete the in-camera raw file you can't recover it. That locks you out of using the camera manufacturer's own converter, and can sometimes cause problems with third party raw converters (there are cases where an original raw works correctly, but one translated to DNG doesn't). It may also be problematic if you ever want to enter a competition or deal with a news agency that requires you to submit an in-camera raw file to verify your image is not manipulated - a DNG may not be acceptable. Personally, I would not delete the original raw.

[zeitz]

2 hours ago, 01maciel said:

When I compare EXIF information side-by-side of a RW2 file and the converted DNG it shows lots of differences.

Interesting discussion.  What version of the RW2 file are you converting - the original RW2 file or the RW2 file after adding the M-lens information to the EXIF?

You may want to contact Adobe customer support.  I have found them responsive to these types of questions.  It may in fact be an error in Adobe's code.

Readers may get confused with the term proprietary Digital Negative Converter.  Just to clarify, while Adobe's Digital Negative Converter is closed source, the object code application is free to any user who wants it.  It is not associated with any Adobe CC subscriptions.  As you point out it works with any computer OS.

[01maciel]

vor einer Stunde schrieb zeitz:

What version of the RW2 file are you converting - the original RW2 file or the RW2 file after adding the M-lens information to the EXIF?

I just tried both and found out that it makes no difference whether I convert the original RW2 or the RW2 incl. the added lens information.

vor 1 Stunde schrieb Anbaric:

Personally, I would not delete the original raw.

I noticed that the original RW2 file is 66.6MB big whereas the converted DNG file is 'only' 50.1MB. It may be redundant information which got lost during conversion or some information is gone for good. I suppose it is a good idea to keep on with the RW2 files.

[Anbaric]

36 minutes ago, 01maciel said:

I noticed that the original RW2 file is 66.6MB big whereas the converted DNG file is 'only' 50.1MB. It may be redundant information which got lost during conversion or some information is gone for good. I suppose it is a good idea to keep on with the RW2 files.

I suspect that's mainly due to better compression of the raw data by the DNG converter - the metadata tags won't take up much space.

[jaapv]

For instance Xrite software does not recognize RW2. You have to convert to DNG which only works by dragging the file onto the Converter icon.