Metadata Date Time

Question

I have set the time in my 5D III to London with the daylight savings time modification activated.  I live in the Eastern Time Zone.  There are four different date/time entries in my Metadata panel with current entries from one image shown.  I am unable to find any information about how these operate.  They are:
Metadata Date                  8/18/2012 1:20:39 PM
Date Time Original            8/18/2012 4:49:58 PM
Date Time Digitized           8/18/2012 4:49:58 PM
Date Time                         8/18/2012 1:20:39 PM
As shown the “Metadata Date” and “Date Time” have been changed from UCT to EDT, but these times are different from “Date Time Original” and “Date Time Digitized” by 19 seconds after accounting for the time zone difference.
Can someone give some light about these entries and how they work?
Thanks,
Wil

Answer 1

Not all but some of the information for which you are asking.
 Date/time original specifies when a photo was taken
 Date/time digitized specifies when an image was digitized
 Date/time modified specifies when a file was modified by the user
http://www.metadataworkinggroup.org/pdf/mwg_guidance.pdf Page 37
Is a good starting place.