Android has a protocol called Android Beam where NFC is used to negotiate transfer which is then moved to either Bluetooth or WiFi Direct. That's probably what cameras are using.

Between phones you tap them together while a picture / video is open (which is admittedly less elegant than AirDrop... although significantly more reliable in my experience).

Good point; you're probably right and I'm probably wrong, since I'm recalling seeing videos that demonstrate how NFC works w/ cameras on Android versus iOS. I do have an iPhone, so to get pictures from a camera I have to (usually) manually select the camera network, then go to the app, then start downloading.

The clunky software camera companies ship doesn't help, of course. If I were in charge of a camera company I'd publish an API and SDK and welcome the world's many hackers to make the camera better, but alas I'm not and no one asks my opinion.

NFC is used to transmit the login credentials, which is fairly nifty actually.