FocusTwist attempts to turn your iPhone into a Lytro Light Field camera, complete with photos that can be focussed after you take them. How does it perform this technological magic? It cheats.
The app takes a pragmatic approach: it brackets focus. That is, it snaps several pictures of the same scene and combines them. Then, when you share the result via Twitter, people can tap on an object and it’ll snap into focus.
It’s not perfect. You’ll have to keep still while the app shoots the shots, and if anything is moving in the scene it’ll move when people view the image. But it’s $2, and you don’t have to carry another camera with you.