Your iPhone is already a pretty decent mini camera on its own. But you could get even better shots if you add lenses and the right apps to your device. The 1.33x Anamorphic Adapter is another cool accessory you can pick up to capture wider shots.
The Anamorphic Adapter transforms native 4:3 aspect ratio to panoramic 16:9 in still mode (with software de-squeeze). It works on videos too. It expands horizontal field of view (FOV) of your camera by 33%. The Anamorphic Adapter for iPhone 5s has an all-glass optical design with anti-reflection coatings. You can find it on Kickstarter.