It's not clear to me, Part IV

This is a sample of a new "living photograph" created by a light field camera. After it loads on your computer, you can click on various parts of the image and it will focus on that part of the image. (This is actually a Flash video that simulates what an actual graphics processing program will be able to do with images captured by this light field camera.)

For example, if you click on the red part in the center, the image will sharpen up and you will be seeing "through" the glass panel at the person on the street. The glass will vanish.

If you click on the grey rectangle at the top left corner of the picture, the focus will shift back into the room and you will no longer see the person on the street clearly. You will see the glass that's in-between you and the street.

I did read most of inventor Ren Ng's 203-page doctoral dissertation, to save you the time and effort. I found a formula that might explain the after-the-shot focus trick for you:

 Or maybe it won't explain things - this math is WAY above my head.

Here's my take on this concept - a conventional camera allows you to capture the light that hits on the sensor (or film). You as photographer have to be sure the light is correctly focused when you capture it.

In essence the Light Field camera captures all the light that enters into the body of the camera. The processing software allows you to move back and forth in space along those light rays that are inside, thus changing the focus and depth of field.

Ng quotes photographer Henri Carter-Bresson:

The creative act lasts but a brief moment, a lightning instant of give-and-take, just long enough for you to level the camera and to trap the fleeting prey in your little box.

With this new digital light field camera we can solve that problem by catching lots more "prey in your little box". Then we can reach in and grab the specific thing we want.

He finishes by saying:

... the main price to pay for this new kind of photography is recording and processing a lot more data. Fortunately, these kinds of challenges map very well to the exponential growth in our capabilities for electronic storage and computing power.

I will have to ask the boss about getting me a new computer and camera!