Basically they let you take a picture and chose whatyou want to have in focus. The focus can be changed anytime after the picture is take. An example is given in the source and more on the website.
Have you ever taken a picture that would have been great if only it were in focus? Of course you have. So have we, countless times. But those days may soon be past all of us with the introduction of Lytro, an entirely new kind of camera that allows users to completely change the focus of a picture after the shutter clicks. And, according to AllThingsD, this next-generation camera will be available before the end of the year.
The secret behind the Lytro camera is a new type of sensor that gathers much more information about the light coming into the camera than the sensors found on all other types of digital cameras. Rather than record a finite amount of information about the light in a photograph, as is the case with other camera sensors, the Lytro sensor records the entire