A new app called FocusTwist by Arqball lets your iPhone do what a US$400 Lytro light field camera is used for. Like the Lytro, the FocusTwist app lets you adjust the focus a picture after you have taken it. However, the method of after-focusing is completely different in FocusTwist than it is in the Lytro. The Lytro uses specialized hardware and software (you can read about it here
