Light Field Photography

This week I wanted to write about a new style of photography that I have recently started playing with, called Light Field photography.

A light field camera, also known as a plenoptic camera, captures information about the light field emanating from a scene; that is, the intensity of light in a scene, and also the direction that the light rays are traveling in space. This contrasts with a conventional camera, which records only light intensity. In this first image, the focus is on the little plaque on the table.

The first light field camera was proposed by Gabriel Lippman in 1908, and he called his concept “integral photography”. Lippmann’s experimental results included crude integral photographs made by using a plastic sheet embossed with a regular array of microlenses, or by partially embedding very small glass beads, closely packed in a random pattern, into the surface of the photographic emulsion.

In 2004, a team at Stanford University Computer Graphics Laboratory used a 16-megapixel camera with a 90,000-microlens array (meaning that each microlens covers about 175 pixels, and the final resolution is 90 kilopixels) to demonstrate that pictures can be refocused after they are taken.

Lytro Inc. was founded in 2006 by Res Ng, a graduate of Stanford University and inventor of the Lytro Light Field camera line. My second image here is the same shot as the image above but with the image re-focused on the Diet Coke can in the foreground.

Features of a light-field camera include:
1) Variable depth of field and “refocusing”: Lytro’s “Focus Spread” feature allows the depth of field (depth of focus) of a 2 dimensional representation of a Lytro image to be expanded after a picture has been taken. Instead of having to set the focus at a particular distance, “Focus Spread” allows more of an 2D image to be in focus. In some cases this may be the entire 2D image field. Users also are able to “refocus” 2D images at particular distances for artistic effects. The ILLUM allows the “refocus-able” and “Focus Spreadable” range to be selected using the optical focus and zoom rings on the lens. The ILLUM also features “focus bracketing” to extend the refocusable range by capturing 3 or 5 consecutive images at different depths.

2) Speed: Because there is less need to focus the lens before taking a picture, a light field camera can capture images more quickly than conventional point-and-shoot digital cameras. This is an advantage in sports photography, for example, where many pictures are lost because the cameras auto-focus system cannot be kept pointed precisely at a fast moving subject.

3) Low-light sensitivity: The ability to adjust focus in post-processing allows the use of larger apertures than are feasible on conventional cameras, thus enabling photography in low-light environments.

4) 3D images: Since a plenoptic camera records depth information, stereo images can be constructed in software from a single plenoptic image capture. This third image is an image from a wedding shot by a photographer using the Lytro camera. Notice how they were able to switch the focus between the bridge and groom.

I have recently started using a Lytro Illum camera myself and I like the camera a great deal. Is it perfect for every situation, probably not, but one of the nice aspects of the camera is if you are shooting sports, you can shoot faster with the Lytro Illum as you don’t have to worry about whether or not the AF can keep up. Since the images can be re-focused in the camera or Lytro’s Desktop processing software, you can just shoot away at a football game and then put the images in proper focus later. Some wedding photographers have begun to embrace the Lytro camera as they can take one shot of a bride and groom like this sample image and shift the focus from him to her in a single shot and then export both versions for print.

I have had my Lytro Illum for a few weeks now and I can say that the camera is certainly worth a try, I have captured some really fantastic images with it. Is the Lytro Illlum for everyone? Of course not, but if you have the extra $350 to spend and want to take your creativity to the next level, go ahead and give it a try!