I was considering investing some money on an external GPS tracker to tag my photos. Eventually, by browsing on internet I just realized that I have been carrying my GPS tracker with me all the time: my iPhone. I just tested the workflow with Nikon photos, it worked just fine. So I would like to share this trick here in case some people want to do the same. This idea has been around for quite some time already, but I could not find in any posts in this forum yet.
For those who have an iPhone, the beauty of this method is that since it is your cell phone, in principle, it is always with you in the field. The best part is: it is typically charged already. You don't need to worry about recharging the battery of an external device whenever you want to use it.
You only need two easy-to-use applications:
1) GPS Stone for iPhone: it is free, works beautifully with no advertisements.
2) GPSPhotoLinker: Free Mac application. Again, works perfectly with professional results.
Just use the iPhone app to track the GPS coordinates in background mode, you can keep it running for as many hours as you want, perhaps days! After finishing shooting your DSLR photos, just export the GPS coordinates from within the iPhone app to you by e-mail. When you import your photos on the computer. Just launch the GPSPhotoLinker that will quickly geotag all your RAW or JPG photos using the GPS file you received by e-mail. It works great without any hassle!
Ok, I am a Mac user with an iPhone. If you have a PC and/or another smartphone. I am pretty sure you can do the same, just need to look for it on the web.
I hope this is helpful in anyway.
Finally, these two apps are free. However, if you think this workflow works fine for your needs, please consider buying the pro iPhone app and/or donating some bucks to the Mac app developer.