You know how it is on vacation. You take your camera, shoot pictures, and when you get home you see that you forgot to set the date/time on your camera. Even worse: your wife also took a camera with her, and she actually read the manual and set the time correctly. So now you have two sets of photos with mismatching date/times. Now what?
It turns out that there is actually a pretty simple trick to solve this, and you don’t even haven to install exiftool or do funny command line voodo. If you have iPhoto and a mouse, here’s what you do: