Which app of that name? There are two or three. Thanks!I use a free iPhone app called GPSRecorder that I just fire up when I want to tag what I'm shooting.
As long as your camera time is in sync with your iPhone then it works great.
The app allows you to easily export a gpx file that lightroom etc accepts.
The smart phone logs your GPS co-ordinates and time capture. At the end of your photo expedition you take a picture of the QR code GPS4Cam generates.Not meaning to hijack this thread, but can someone explain to me how GPS4CAM works? There's an "overview" on the website, but it's not very clear.