P: Addition of selection to the Sort on the Library tab

[Creekwood]

Add the 'Date Time Original' EXIF data value to the list of availabe sort selection criteria on the Library tab. This should be both the date and time value sorted as one field. 

[johnrellis]

You can sort photos by capture date/time (when the shutter was pressed) by doing View > Sort > Capture Time.  (The Sort options are also available in the toolbar at the bottom.)

LR's notion of capture date/time is always EXIF:DateTimeOriginal if it's present in the photo. If it's not present, it uses other fields in the photo (the precise list of which I don't have handy).