Ren Ng is founder and CEO of a new start-up company called Lytro. They expect to have a camera on the market some time later this year that will let you take a shot and then figure out how you want to focus it later. You'll also be able to simulate a 3D photograph.
A regular camera takes in the sum of all the light rays it perceives. Ng's camera uses something called light field technology, which measures each ray separately and records its color, intensity, and direction. That allows the photographer to choose which rays to manipulate and how -- thus changing the focus on the shot.
It helps to think of it like a group of musicians going in to record a song. Traditional cameras are like the whole band going into a room with one microphone recording everything that happens. The light field camera is more like putting each musician in a separate room and recording multiple tracks. That way you can turn up the bass a little, take out the low end on the drum, add some reverb to the vocal, whatever you want to do.
This is a technology that has actually been around for a while but it took dozens of cameras and a lot of expensive computer equipment. Ng worked on this issue as part of a doctoral thesis at Stanford and started his company after graduating. He says he was able to replace a lot of hardware with software and develop a sensor that was capable of separating the light rays.
Ng says his camera will be available later this year and will be priced comparably to other consumer cameras.
Also in this program, and more along the lines of technology you may not want, SMELL-O-VISION! It is what you think it is.