Light-Field Photography

This March brought the first major update to camera design since the dawn of cheap digital photography: a camera that lets you adjust the focus of an image after you’ve taken the picture. It is being sold for $399 and up by Lytro, a startup based in Silicon Valley that plans to use its technology to offer much more than the refocusing trick—options like making 3-D images at home.

All consumer cameras create images using a flat plate—whether chemical film or a digital sensor—to record the position, color, and intensity of the light that comes through a lens. Lytro’s camera does all that, but it also records the angle at which rays of light arrive (see graphic). The resulting files aren’t images but mini-databases capturing the three-dimensional pattern of light, called a light field, at a particular moment. Software can mine that database to produce many different possible photos and visual effects from one press of the shutter.

Lytro has wrapped its technology in a consumer-friendly package, making this new form of photography more likely to catch on.

Light-field cameras existed before, but they had limited industrial uses and were never cheap enough for consumers. Lytro founder Ren Ng, who worked on light-field technology for his PhD at Stanford University, made this one affordable by simplifying the design. Instead of using multiple lenses, which made previous light-field cameras expensive and delicate, Ng showed that laying a low-cost plastic film patterned with tiny microlenses on top of a regular digital sensor could enable it to detect the direction of incoming light.

Recording the entire light field entering the camera means that images can be focused after the fact: a user can choose near, far, or any focus in between.

Refocusing images after they are shot is just the beginning of what Lytro’s cameras will be able to do. A downloadable software update will soon enable them to capture everything in a photo in sharp focus regardless of its distance from the lens, which is practically impossible with a conventional camera. Another update scheduled for this year will use the data in a Lytro snapshot to create a 3-D image. Ng is also exploring a video camera that could be focused after shots were taken, potentially giving home movies a much-needed boost in production values.

Images from Lytro cameras can be shared on websites and Facebook in a way that allows other people to experiment with changing the focus to explore what the photographer captured. This kind of flexibility is so appealing, Ng says, that “in the future, all cameras will be light-field-based.”