Light Field Photography with Lytro


I’ve always been interested in photography. When I was young I used to read books full of theory about ASA film speeds, f-stops and depth of field calculations. One book said that there was no chance that a camera would ever be able to focus itself. I really wish I’d kept that one.

Anyhoo, I’ve just found out about Lytro. This is a new way of taking pictures they are calling “Light Field Photography”. Rather than using a lens to capture a single, hopefully well focused, image on a sensor, what Lytro are doing is capturing the entire “Light Field” from a scene. The blurb (and this highly detailed thesis) say that the camera captures not just the light, but the direction it is coming from. This means that by using cunning computation they can then built up an image which is focused after it has been taken. The photographer can make decisions about which parts of the picture they want to have sharp after the shot has been taken. They have some astonishing demos on their web site where you can click on different parts of the picture to focus at that point.

I’ve had a read of the thesis and I think what they are doing is putting a bunch of tiny “micro-lenses” in front of the sensor so that different parts of the sensor are focused at different distances. This means that you lose resolution (since the same spot in the image is being focused at different points) but by selecting the output from particular sensors you can build an image focused at any point, or indeed build up an picture that is sharp at all points. This requires a fairly ferocious amount of processing power, but does give you a lot of flexibility after the picture is taken.

I’m not completely convinced by their pitch. Modern cameras with small sensors have a large depth of field (most of the image tends to be in focus anyway) and they also have very efficient auto-focusing software. However,  I’ve clicked the box that says “Let me know when the cameras are for sale” and we will just have to see how it all turns out.