What's the difference between CreateDate and DateTimeOriginal

[ibex]

I'm in the process of renaming a block of photos and want to reset the dates back to when the photos were taken.

I'm unclear about the distinction between CreateDate and DateTimeOriginal - which one is the most reliable indicator of when the photo was taken or is there another tag I should be using?

Is there a document anywhere that describes the definitions of the various exif tags?

[StarGeek]

For digital cameras/phones, they should be exactly the same value. If they're different, then something has edited the file incorrectly, and there really isn't a way to know which is the actual time.

The CreateDate tag (called DateTimeDigitized by the EXIF spec) is the date/time that the digital file was created. The DateTimeOriginal tag is the date/time when the image was created.

Technically, the only time they should be different is when the image was taken with an analog/film camera.  The moment the picture was taken would be the DateTimeOriginal.  Then, when the photo was scanned into the computer, that would be the date/time it was digitized, the CreateDate.

In practice, though, I don't think anyone cares enough about the details to differentiate between the two. Except maybe for a place like the U.S. National Archives or similar organization.

Not yet mentioned is the ModifyDate (called DateTime by the EXIF spec).  This is the time stamp for when any modifications are made to the actual image data, such as cropping, editing, etc.

[ibex]

Thankyou.  That helps a lot.