I have a related problem (or so I believe). I have a database in Thumbsplus that I want to migrate. I managed to put the Capture date from the database into an unused IPTC field (say CREDIT) as a string of the format "2008:01:29" or (for some images) "2008/01/29" for each image. This date is different from the DateTimeOriginal field, and that is my problem for Lightroom (where I am migrating to). I am trying to change all Date fields in the images to the date stored in IPTC:Credit by

exiftool -S -s -Credit a.jpg | tr '/' ':' | exiftool -d "%Y:%m:%d" -AllDates'<=-' a.jpg

Ideally, I'd like to shift the time by +1 hour, too, but I could not figure out how. This does work for a couple of images (say 30% out 10,000) but for the majority I get an error message about minor (?) MakerNotes errors and the image does not change. Sometimes it does not work at the first time, but if I keep trying it is done afterall. I tried to delete the MakerNotes before I apply the above, then it runs through cleanly. But this I really do not want as I'd like to preserve the Makernotes.

Can I jist use the -m option and trust that all will be well (for 10,000) images? Any help appreciated-

Thanxx, Mixx