exif timezoneoffset

[Alan Clifford]

I can find reference to timezoneoffset in https://exiftool.org/TagNames/EXIF.html and in the history from 2006 but I cannot find it in the Exif Version 2.32 document,  https://web.archive.org/web/20190624045241if_/http://www.cipa.jp:80/std/documents/e/DC-008-Translation-2019-E.pdf

Has this tag been deprecated now that offsettimeoriginal exists?

The reason I ask is because the jpegs produced by motion, https://motion-project.github.io/index.html, from my Raspberry Pi include it and it is a tag I was unaware of.

[StarGeek]

If you check on the EXIF tag page you linked, you'll see that TimeZoneOffset is not underlined.  From the text at the top of the page
   Also listed are TIFF, DNG, HDP and other tags which are not part of the EXIF specification, but may co-exist with EXIF tags in some images. Tags which are part of the EXIF 2.32 specification have an underlined Tag Name

I believe it was never part of the EXIF specs.

[StarGeek]

Ah, found this post from Phil which links to where it was documented.  The link is since dead, but it was archived by the Internet Archive.

[StarGeek]

Further exploration of that Broomscloset.com through the Wayback machine came up with these two related PDFs.  Linking so as not to lose them.
Picture Transfer Protocol
ISO 12234-1 Photography - Electronic still picture cameras - Removable memory - Part 1: Basic removable memory reference model

[Alan Clifford]

If being thinking about using it but I'm not sure how to read it as it can have one or two values.

Being specific, I already have

$exifTool->Options(Duplicates => 0, IgnoreMinorErrors => 1);
@dtotags = ( 'xmp:DateTimeOriginal', 'exif:DatetimeOriginal', 'exif:OffsettimeOriginal',
   'composite:DateTimeOriginal', 'quicktime:createdate',
   'nikon:DateTimeOriginal', 'nikon:timezone#', 'nikon:daylightsavings#',
   'file:filemodifydate' );
$dtoinfo = $exifTool->ImageInfo($photofilespec, \@dtotags);

$xmpdto = $$dtoinfo{$dtotags[0]} if defined $$dtoinfo{$dtotags[0]} ;  # could be zero or undef
$exifdto = $$dtoinfo{$dtotags[1]} if defined $$dtoinfo{$dtotags[1]} ;  # could be zero or undef
$exifoto = $$dtoinfo{$dtotags[2]} if defined $$dtoinfo{$dtotags[2]} ;  # could be zero or undef
etc, etc


I need advice please on how to read the first or the only value of timezoneoffset.

[StarGeek]

The only reason I have that embedded in any of my files is because Geosetter would set that tag. Since the newer tags became available, I've set them and cleared TimeZoneOffset.  I've never seen it on any file I've collected from the net and I don't think there's many programs that support it.  I have seen support for the official EXIF tags, though.

I can't really help with the code, but I would assume that it's returned as a simple string of one or two numbers, as the tag can only hold 1 or 2 integer values, not actual timezone data.  You could then just split on the space.

[Alan Clifford]

I thought of another way.  My scripts for processing photos look for a last resort file that contains timezone data.  So I've created a simple bash script to create that file, with the time zone from the date command, when I create the daily directory on the Raspberry Pi running the camera.