Arqball has FocusTwist (iTunes Link) for the iPhone and iPod Touch in the iTunes App Store for FREE (regularly $1.99) for a limited time.

Focusing an image after you take it works great on for food, toys, fashion, nature, architecture – any scene with multiple elements to focus on.

For best results, compose a scene with something interesting very close to your phone’s camera (3-4 inches away) and another element further away (> 5 feet).