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The Lytro camera: Too little for too much

The new Lytro camera implements a really novel technology: Light field imaging. It's a great idea but the product is disappointing.

By , Network World
March 28, 2012 01:59 PM ET
Gibbs

Network World - My editor will be glad to know that this week, in contrast to the last few Gearhead columns I will not be discussing AT&T, ADSL (+ or otherwise), or Motorola DSL modems.

Nope, this week, something completely different: The Lytro camera, which is based on a really geeky, way cool, leading edge piece of research; light field photography.

Actually, it's only leading edge because the technology that makes it possible has only been around for a couple of decades. The original theoretical foundations were laid out way back at the turn of the last century.

What's so interesting about this technology is it not only has a place in the consumer world, but it will also be a boon in the business world simply by making it incredibly easy to take good photographs that will always be in focus.

The underlying principle, the light field, is the concept that a scene is comprised of all the rays of light, no matter what direction they are heading. A conventional camera captures only a restricted subset of these rays that are focused by the lens onto the imaging device in the camera, and while the color and intensity of rays are recorded, all of directional data about where the rays came from is ignored.

Conventional camera systems have a focal "plane", the point in front of the lens at which objects are perfectly in focus. The amount of light and other factors determine the "depth of field," the zone that extends in front of and behind the focal plane where, as far as the human eye is concerned, objects are apparently in focus. Anything outside of this zone will appear blurry.

A light field camera uses a very different imaging system that consists of, as Wikipedia explains: "an array of microlenses [placed] at the focal plane of the camera main lens. The image sensor is positioned slightly behind the microlenses. Using such images the displacement of image parts that are not in focus can be analyzed and depth information can be extracted."

So, by analyzing many tiny images and then using software to cleverly manipulate and combine them into a single image, a light field camera can capture, in effect, an enormous depth of field. This means an image captured by a light field camera can be used to create other versions of the image with, in theory, any focal plane and depth of field. So you could use a light field image to create versions where the foreground, mid-ground, or background objects are in focus. Even more intriguingly, at least in theory, a light field camera could even produce an image where everything in the scene is in focus!

This ability of light field imaging technology to produce "refocusable" images means that the ultimate "point and shoot" camera could be built ... no focusing, no aperture adjustment, just, er, point and shoot.

But, there's a potential problem. As the Wikipedia entry explains "The drawback of such a system is the low resolution that the final images have. As one microlens samples the light directions at one spatial point an increase in the number of image pixels can only be done by increasing the number of microlenses by the same amount."

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