The Nokia Refocus camera app allows you to shift the focus after you have taken the photo, similar to what the Lytro camera does. The big difference is that, unlike the Lytro which basically is a hardware implementation with software to back it up, the Refocus camera app works by simply taking several different images at different depths of field when you press the shutter release button on your phone. When you then click on the image to select where you want to reposition focus, the app (software) simply select one of the images which have the object you clicked in sharp focus. It’s a clever implementation and avoids the costly physical implementation of the Lytro.
Read more at: phys.org.
