I'll clarify in the hope of helping anyone who works with digital photos:
Having tested working with dates of probably 15 million digital photos, I can assure you that the EXIF DateTimeOriginal field is by far the most reliable indication of when the shutter was pressed on a camera.
I do find many other date fields useful for various other purposes.
But for the organizing tasks mentioned in this Topic, like renaming files (renaming photos starting with the date is a common practice) and sorting photos into folders by date, it's the only field that should be used for those tasks.
EXIF DateTimeOriginal is the first field photo applications check for a photo's date when determining what date to display in the field applications label as 'Date Taken', Capture Date', 'Timestamp', etc.
Other date fields that do initially display the date the shutter was pressed, including file/system Date Created, Date Modified, and Exif Modify Date can change when a photo is:
- Converted to another format.
- Edited.
- Moved to another drive with a different format.
- Downloaded from cloud storage.
But none of those actions will change the EXIF DateTimeOriginal.
A photo can have a 'Date Taken' or 'Capture Date' but not have an EXIF DateTimeOriginal, so the dates displayed in those fields for photos without an EXIF DateTimeOriginal can change.
I don't consider other fields, like IPTC DateCreated, to be reliable because not all applications look at that date field.
The photos I organize for clients are typically gathered from old computers, hard drives, CDs, thumb drives, Google Photos, Dropbox, Apple Photos, and other Sources.
Between 5% and 20% of photos in every collection I have organized lack a date in the EXIF DateTimeOriginal field. Every one of those photos will display a 'Capture Date' in applications that use that field. In applications with a 'Date Taken' field, like Directory Opus and File Explorer, a date will be displayed for some photos without an EXIF DateTimeOriginal field if, for example, they were converted or edited.
So, EXIF DateTimeOriginal is the only date metadata field I have found to be a reliable indication of when the shutter was pressed.
However, an EXIF DateTimeOriginal (and other date metadata fields) can be wrong if the camera date was not properly set.