Ren Ng, graduate student at Stanford University has developed a hand-held plenoptic camera which takes a shot first and allows you to make the decision about focus point in software after the event. The prototype camera is actually a Contax 645 with a modified Megavision FB4040 back (sixteen megapixel). The back has had an array of 90,000 microlenses mounted in front of the sensor (with a gap between the array and the sensor). These microlenses create a unique image on the sensor surface which includes not only the amount of light deposited at that location, but how much light arrives along each ray. The image is then reconstructed in software and a focus point can be chosen. Note that the final resolution is the same as the number of microlenses.
Check out the videos to see it, it's awsome.
http://graphics.stanford.edu/papers/lfcamera/refocus/
