DNG Converter = Time Machine?

[Marc Sabatella]

Has anyone else experienced issues with the standalone Adobe DNG Converter changing the EXIF date in your images?  I just discovered that it has been doing this to my images for the last several months (ie, as long as I've been using it).  I saw a reference to some sort of time zone bug in the Adobe forums, but I am having trouble accessing them.

Marc Sabatella

[peterkrogh]

Mark,
I have not noticed this, but it would not surprise me too much.
That time zone thing seems to be implemented differently by different manufacturers.  A real pain.
Peter

[Marc Sabatella]

I'm having trouble finding anyone else with the same problem, so it does make me suspect there is some sort of setting I have that is messing things up, but so far, I've been unablet o find a way to actually correct the problem.  But I *have* managed to figure out something of a workaround.  It turns out if I first generate XMP sidecar files for my RAW files, and those XMP files contain the correct EXIF timestamps, the DNG converter will use those rather than then the ones embedded in the image file.  My adaptation of the DAM Book workflow for ACDSee Pro 2 had me converting to DNG during the image ingestion phase, because ACDSee's use model was such that it made more sense to do this before entering any metadata.  So what I am doing now is entering the location and copyright/contact information (only) immediately after ingestion on my proprietary RAWs.  This generates XMP sidecars that includes EXIF timestamps, so I can then then convert to DNG and get accurate timestamps.

[Marc Sabatella]

I still don't understand the situation completely, but I can now verify that the DNG converter *is* changing the EXIF timestamp info.  Specifically, it is adding EXIF fields to the XMP area, copying the time unaltered from the original EXIF fields, but appending timezone info taken from one's Windows settings to the time/date digitized.  And this is causing some XMP-aware utilities (including, but not limited, to, ACDSee) to *report* the time in GMT equivalent instead of local time.  To what extent that is reasonable is another matter, but apparently, there is not as much standardization as one would hope for in terms of how time zone information is handled with EXIF.  So for now, I'm content to chalk this up to different manufacturers interpreting things differently, and as long as I can get the tools to produce the results I want - and the workaround I mentioned does seem to do this - I'm not going to worry about it.

But for anyone else using the DNG Converter - and perhaps other Adobe products - you might want to be aware of this.  The upshot is that the timezone of the computer on which you generate the DNG gets hardcoded into the file.  I suspect that would allow some utilities to do clever things like display the EXIF info in *local* time, but it would be based on offset from the time zone of the computer on which you converter to DNG, not on any notion of where you actually took the picture.

Marc Sabatella