If you have the iPhone 5S, you should try taking a video in Slo-Mo mode, then moving the IN and OUT points to touch each other when watching the video. It keeps it in 120fps, and doesn't convert it to 30. You can even share/transfer the video in full 120gps glory.
I think this is the BEST new feature of the iPhone 5S
I think this is the BEST new feature of the iPhone 5S