Ive been searching for an app like this ever since the first iPhone. It is very strange that Apple does not have this feature built-in already. While this is a very good app, it does not make use of the +- volume buttons to take pictures or start/stop video recording. This really defeats the purpose of the ability to hold the phone vertically to take videos using only one hand. The Tilt-to-zoom function is very clever. But, just like Apples inexplicable videocam design, there is no Pause function in Horizon either. The "Tutorial" is essentially a joke. Other than that this is a pretty solid app that still has room to improve. Designers should try using this app with only one hand to figure out where improvements are needed.