Cameras which doesn’t have inbuilt geo tag capabilities can be supplemented with your phone if your phone has in built GPS.
Both paid and Non Paid solutions uses the same logic. Before a photo session, just turn on the geo position tracking which starts to record geo data through out the session. Some apps also provide battery saving tips. The geo positioning data can be exported from these apps in gpx format. Which will be later given as input to the computer software which maps the geo location data to the photos.
The best paid option I could find is from Geotag Photos Pro available both for iPhone and Android.
Non Paid Solution
You can use the following apps to record your geo position and let it run through out your photo session. Sure it costs batter but If you need geo tagging, then it is the sacrifice one needs to make. You need two softwares one is for your phone
myTracks – The gps Logger – Free – IOS
mytracks – Free – Android
GPS Logger 2 – Paid – IOS
Kinetic GPS – Paid – IOS
GPS Photo Linker – Free – Mac
There is also another solution to look in to which seems to be free http://gps4cam.com