With its 1080p capabilities, the iPhone 4S is a pretty good option for on-the-go HD video recording. However, it’s certainly no entry-level DSLR—due to its limited functionality—though apps increasingly enhance the camera. Take SloPro, for instance. A new app, it allows any iPhone 4S owner to shoot slow-motion video at 60 frames per second, toggling the speed as you record. A built-in editor even allows users to trim video clips, as well.
SloPro is available for free in the app store… ( but you will have to pay $1.99 to upgrade to the Pro version. But only if you want to remove the watermark from the videos you shoot with the app and need some more options for exporting the vids )