iOS users can only use zoom functionality in the stock app, before they started recording a video, but all of that is about to change thanks to iOS 7. The first beta allows users to use zoom functionality while recording a video in the redesigned Camera app
Upon hitting the big red red button to start recording, simply use the pinch gesture to zoom in and out during video capture. You can also tap-to-focus on your closeups as you’re shooting video.
To zoom out footage, pinch out anywhere on the screen or use the handy slider at the bottom part of the interface. Unfortunately, the slider doesn’t appear until you zoom in on the video.