Photos from two cameras do not sort properly by "oldest first."
Prior to going on holiday with my wife I precisely synchronized the date and time on our two cameras. Once I returned home I imported photos from both cameras into a common album in Photos. When I sort them by "keep oldest first" they do not sort strictly by the date/time that the photo was taken (as reflected in the "info" for the photos). Instead, the photos from one camera are shown sequentially followed by the photos from the second camera that were taken about the same time. This throws off the chronological order of the photos when viewed. Any suggestions?
iMac, OS X El Capitan (10.11.3)