The app works by capturing a couple of seconds of video and then allowing you to mask over the details that you’d like animated. It’s surprisingly satisfying.
Cinemagraphs aren’t new (there are some nice examples on Jamie Beck’s tumblr photoblog), but I wasn’t aware of such a simple way of making them before now.
It’s a pretty straightforward process, with a couple of catches. Firstly, everything needs to be pretty still, and the details that move should move in place rather than moving around the frame. The second thing to be aware of is that in order to create a seamless animation, the movement is played forwards and then backwards on a loop. This is quite evident on the example (of Kat in KFC earlier) above – notice how she sometimes blinks ‘backwards’.
At time of writing, it is free in the UK iOS App Store.