The problem: you return home from a vacation and took a lot of pictures. But not with a single camera. But you now want all images in one place, in chronological order. Here is what to do.

1. Get the images from the cameras using PTP or MassStorage copying. Store the photos into separate directories (sony and canon)

1. photograph the clock of the more precise camera (Sony) with the other camera (Canon)
2. Use exiftool to read the EXIF date of that picture and compare it with the photographed time
3. Adjust the time of the photos (Canon) to match the clock of the more precise clock (Sony):

   # substract 5 minutes and 2 seconds from all dates:
   exiftool -AllDates-='0:0:0 0:05:02' -overwrite_original canon/*.JPG

4. Move Canon Panorama Images to a sepearate dir

   mkdir pano
   mv canon/ST* pano/

5. Create an output directory out
6. Rename all files to their creation date and move them to the out directory

   exiftool '-FileName<DateTimeOriginal' -d out/%Y%m%d-%H%M%S-canon%%-c.%%e canon/*.JPG
   exiftool '-FileName<DateTimeOriginal' -d out/%Y%m%d-%H%M%S-sony%%-c.%%e sony/*.JPG

1. Get the Tracklog from the GPS's card and convert NMEA to GPX:

   nmea2gpx.pl gpx/*.TXT

2. Take a photo of the GPS clock with the default date camera (sony)
3. Use exiftool to read the EXIF date of that picture and compare it with the photographed time
4. Geotag the photos, optionally also set some clear text location tags:

   # Camera is 2 hours and 2 seconds ahead of GPS's GMT
   for GPX in gpx/*.gpx
   do
     gpsPhoto.pl --dir out --gpsfile $GPX --city 'Rome' --country 'Italy' --timeoffset 7202
   done