Interesting Exif data, for the deep diver

[DaveSee]

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Hiyas,

 

Most of you use computer software that "hides" the nasty bits, but for some you may find that the DNG metadata is ripe for harvest.

 

After Jaime calmed my over-thinking on EV and follow on tests, I looked a bit deeper and found that certain metadata tags would make useful catalog/file store items. Of note are whether "Lens Detection" is "On", and just what the Kelvin temp was recorded, regardless the WB setting. I also determined why my "developed" JPEG and TIFF files were opening with the wrong Orientation in PS(I use Linux, so this is a "Client Problem" solved )

 

First the PS "Orientation" problem(sic): seems the image should have "Orientation="Horizontal (normal)" in the metadata, or it opens "wrong", even if "Portrait", LOL. In C1, etc., this is hidden...

 

There are two tags of interest, fact of history(recording the image), that you do not get, even in the camera "Info" view... OK, one of the two: tag -Camera:Unknown_0x0325 is the boolean for lens detection, and (the one you don't see) 0x0321 is the Kelvin value, even if "Auto" WB is used. There are others, including camera S/N, and f/w "stepping"(1.107 = 4), image number/fire, image number/SD card format, etc.

 

Anyhoo, what prompted me to post is that the metadata tag for "WhiteBalance" is varied across computer software, and it's nice to know that the Kelvin temp, regardless the camera setting, may be grok'd and saved. For my "souping" scripts, I grab this sort of info, then trash the "MakeNotes" when writing the JPEG... who needs to know my camera S/N?

 

fwiw+rgds,

Dave

 

PS-Fedora, DCRaw, NetPBM, ImageMagick and ExifTool are joined with BASH... and calling ICC profiles from J. Holmes and JFI

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[DaveSee]

Hiyas,

 

Most of you use computer software that "hides" the nasty bits, but for some you may find that the DNG metadata is ripe for harvest.

 

After Jaime calmed my over-thinking on EV and follow on tests, I looked a bit deeper and found that certain metadata tags would make useful catalog/file store items. Of note are whether "Lens Detection" is "On", and just what the Kelvin temp was recorded, regardless the WB setting. I also determined why my "developed" JPEG and TIFF files were opening with the wrong Orientation in PS(I use Linux, so this is a "Client Problem" solved )

 

First the PS "Orientation" problem(sic): seems the image should have "Orientation="Horizontal (normal)" in the metadata, or it opens "wrong", even if "Portrait", LOL. In C1, etc., this is hidden...

 

There are two tags of interest, fact of history(recording the image), that you do not get, even in the camera "Info" view... OK, one of the two: tag -Camera:Unknown_0x0325 is the boolean for lens detection, and (the one you don't see) 0x0321 is the Kelvin value, even if "Auto" WB is used. There are others, including camera S/N, and f/w "stepping"(1.107 = 4), image number/fire, image number/SD card format, etc.

 

Anyhoo, what prompted me to post is that the metadata tag for "WhiteBalance" is varied across computer software, and it's nice to know that the Kelvin temp, regardless the camera setting, may be grok'd and saved. For my "souping" scripts, I grab this sort of info, then trash the "MakeNotes" when writing the JPEG... who needs to know my camera S/N?

 

fwiw+rgds,

Dave

 

PS-Fedora, DCRaw, NetPBM, ImageMagick and ExifTool are joined with BASH... and calling ICC profiles from J. Holmes and JFI

 

Replying to my own post because I was wrong--upon inspection of 1.06 f/w based flles--on the f/w "stepping"... two DNG files from the 1.06 era had different 0x0302 values(!). Still, the Kelvin temp remains, among others, constant as a record. FWIW, the "UniqueImageID" tag is volatile... better to get a checksum and record it in the comments.

 

rgds,

Dave