Lytro: The Light Field Frontier

To my astonishment and delight, a truly innovative digital device recently hit the consumer market, and it did so about as quietly as a snowflake landing on cotton. No show-stopping CES announcement. No TV spot during the Super Bowl. Since the twitterati doesn't ignite the blogosphere over a new $400 camera with less resolution and a smaller display than an entry level point-and-shoot, it is understandable how such a device could go underappreciated. Despite the lack of fanfare, a Silicon Valley startup called Lytro released a camera that is likely to revolutionize photography.

The Lytro Light Field Camera's distinctive functionality and aesthetics challenge the prevailing device design paradigm in a way unseen since Apple's first iPod.
It is easy to confuse reiteration with true innovation. Our technoculture has become so focused on specs and gadgetry that we barely distinguish technology that is new from technology that is repackaged. We're accustomed to device reiteration; it happens at regular intervals and in predictable increments. Every six months, Mega Electronics Corp unveils a groundbreaking “innovation” that promises to reshape civilization in a manner unseen since splitting the atom the stone wheel. Inevitably, it's more of the same: more pixels, larger screen, more speed, brighter screen, more memory, smaller footprint—you see where I'm going. The Light Field Camera proudly flies in the face of that trend.
I suspect the Lytro camera may be a relic from the future, sent back to the present as an inter-generational gesture meant to draw imaging pioneers toward a new frontier. Lytro's Light Field Camera literally refocuses the focal point of digital imaging by capturing, processing and presenting photos that possess a spatial dimension that is completely new to commercial photography. Light Field Photography says farewell to static images and bestows upon us the interactive, Living Image.
Click the Living Image below to focus on what true innovation looks like...
Click to refocus; click+drag to shift perspective; double click to zoom. Please be aware that these files are very large and need time to load. It helps to refresh the page more than once.

Light Field Photography

Light Field Photography is a comprehensive system that captures one field of view from several points of view. It does so using a plenoptic lens system that divides the transmitted field of view into constituent rays of light. Instead of capturing a single focal plane, as with conventional photography, Light Field Photography captures light rays that can theoretically interpret any focal plane within the visual scene. These captured light rays form a new kind of digital image, one that can be focused and tilt-shifted after the image has been captured.
Given our common notions about how digital photography works and how digital cameras are used, referring to the Light Field Camera simply as a "digital camera" may lead to undue comparisons and expectations. This device exists alone upon the verge of commercializing a new kind of imaging device—it is neither a point-and-shoot novelty nor an obscure research instrument—it is simply a Lytro.
Like all digital cameras, the Lytro measures the amount of light to strike each pixel of the camera sensor, but it also records the angle from which the light waves reach the sensor as well as the direction by which transmitted light arrives at the camera. The Lytro uses these three dimensions of information to produce an image that is more representative of both the visual scene’s depth and the geometry of objects within the light field. Only light field photographs contain spatial resolution that allows users to refocus the photograph afterimage capture.
Light transmitted by the Lytro's camera lens is refocused by a microlens array (MLA) in front of the digital sensor. This series of microscopic lenses enables the sensor to record the light field from multiple points of view. Combining these variant perspectives into a three-dimensional light map is how a Living Image is conceived. This three-dimensional information preserves the spatial relationship of light waves within the field of view when the camera shutter is pressed. Analyzing the light wave's intensity, angle and direction is the process though which Living Images are born. Not only does a Living Image enable refocusing, it also allows the viewer to shift perspective by clicking-and-dragging the image.

Measuring the resolution of a light field photograph becomes a bit tricky because of an inverse relationship between the Lytro's pixel resolution and its spatial resolution. Optical engineering limitations dictate the resolution of Light Field Technology as a whole; increasing the camera's spatial resolution always accompanies a decrease in pixel resolution. The Lytro image sensor records 11 million rays of light (11 megarays). Photographers can refocus on almost any focal plane within the visual scene; each focal plane has approximately 1.2MP resolution.

The Camera

The differences between the Lytro Light Field Camera and other digital cameras start on the surface. The Lytro is a 4.4 x 1.6 x 1.6” rectangular solid made of anodized aluminum; its rear third is wrapped in a silicone rubber grip and a magnetic lens cap conceals the camera’s objective lens. The only indication of the metal block's purpose comes from a micro-USB icon on the rubber grip. Like the micro-USB port cover, the camera’s objective lens, display screen, zoom control, power and shutter buttons are built discreetly into the streamlined housing.
A fellow writer here at B&H saw the Lytro on my desk and proceeded with rapid-fire guessing, “Is that a flashlight? monocular? rangefinder? flask? pepper grinder? HARMONICA CASE? PENCIL CASE!” I pointed to the power button embedded within the camera’s rubber grip; my coworker removed the lens cap and was snapping Living Images within ten seconds.
When I first handled the Lytro camera, it was obvious that this thing was not a toy. The Lytro is surprisingly substantial. It looks and feels more durable than I expected. Most of that mass is probably concentrated within the rechargeable battery and glass optics. Nevertheless, the fit and finish of the aluminum housing and rubber grip are evidence of quality product design.
The Lytro camera’s unconventional silhouette certainly symbolizes something new to photography. I appreciate the camera’s unique aesthetic, it embodies Lytro’s desire to reshape notions about what a digital camera is. Lytro's product design is more iconic and symbolic than ergonomic. The camera looks great sitting on my desk, but it feels a bit awkward to shoot with. Since the Lytro is more useful to me as an imaging tool than as an attractive paperweight, I worked around its unfamiliar shape until I became comfortable with it. Nevertheless, I still use the included wrist strap as a precaution.
The 1.5" backlit LCD touchscreen includes strengths and weaknesses of its own. The screen itself provides adequate resolution for image playback and capture, but the display is difficult to see unless viewed at eye level. This shortcoming is bothersome but nothing a bit of neck contorting cannot fix.
Optically, the Lytro camera maintains a fixed f/2.0 aperture throughout the entire zoom range. The lens system transmits a 35-300mm equivalent focal length range, thanks to its 8x optical zoom. A touch-sensitive slider in the rubber grip controls zoom adjustments, allowing the photographer to make magnification adjustments in 0.1x increments. Complementing the broad zoom range is the Lytro's impressive close-focus distance, capable of focusing right up to the surface of the objective lens.
The Lytro camera is available in 8GB and 16GB versions, each capable of storing several hundred living pictures—350 for the 8GB, 750 for the 16GB. I have about 250 Living Images stored on my Lytro, and its memory icon appears to indicate more than 25% of available storage space. Considering the 16MB size of each Living Image file and how often I’ve been using the camera, I have been very impressed by both the 8GB storage capacity and run time of the camera’s built-in rechargeable battery.

The Interface

The Lytro's camera settings, exposure control and image review are easily accessible using swipe gestures on the glass touchscreen. Almost every in-camera function is just a swipe-and-tap away, and the Everyday shooting mode is as straightforward as pressing the shutter button. Just like any digital camera, simply pressing the shutter button returns the camera to shooting mode. The camera menus are foolproof, and the swipe gestures offer intuitive response. But if you have thick fingers or a heavy touch like I do, you may be in for some navigation blunders at first.

In Everyday mode, shutter, ISO and focus parameters are automatically set just prior to image capture. This default shooting mode is useful for worry-free photography right out of the box, but leaves something to be desired for those seeking more creative control. Fortunately, the Lytro camera is also equipped with a Creative mode that is a mere swipe gesture away. After I switched my Lytro into Creative mode, it was there to stay. Once they get the hang of the Lytro, most users will probably feel more comfortable in Creative mode; it generally yields better living images, thanks to the enhanced control of the primary focus and spot metering functions.
Although the spatial resolution of a Living Image is the same regardless of the mode used to capture it, Creative mode allows the primary point of focus (and metering point) to be set simply by tapping the LCD screen. Selecting a primary point of focus is great for designating a specific element to pop within the Living Image or simply to set the median distance between foreground and background elements. You will still be able to focus on other focus planes within the Living Image, but the element of primary focus will have the highest degree of detail and will be the default focus point during image review.
For even more creative control, the Lytro camera's manual exposure settings enable Shutter Priority, ISO Priority, and a full manual mode that is supplemented by a neutral density (ND) filter. Since the Lytro imaging engine controls ND filter compensation, results tend to be hit or miss. However, the Shutter Priority and Full Manual modes (without ND filter) reliably deliver the exposure I'm looking for. AE Lock further enables exposure control and helps when composing a shot that has a harsh backlight.

A useful addition to the Lytro Desktop Software is its Living Filter pane, which offers nine distinct Living Image filters. Most of these filters adjust the color characteristics and will dynamically adjust the image upon refocusing, zooming and even perspective shifting. Of the nine Living Filters currently available, three of them were especially useful to me during my month-long Lytro test drive. Blur mode simulates that soft bokeh that wide-open-aperture shooters go for. It also creates a more dramatic separation between the primary focus plane and others in front of and behind the focus point. For me, the Blur filter was useful on most shots, lending a more conventional look to some Living Images. Other standout filters include Crayon and Film Noir. Film Noir is a black-and-white filter with some Blur-like qualities along the edge of the image, whereas Crayon is an interesting filter that saturates the color of Living Images, depending on the selected focus plane.

Overall, the Lytro Desktop Software is a passable digital image repository. It is easy to navigate the software functions as well as manage your library of Living Images. And, like the camera firmware, the desktop software has been regularly updated with useful new features. The most exciting new feature is the Perspective Shift processing capability. It can take several minutes to run a single image through the perspective shift processor, but it certainly makes for some click-and-drag amusement once the 11-megaray interactive image has finished compiling. Perspective-shift interactivity is certain to delight tablet users.
Once the desired focus point has been set in the desktop software, a 1080 x 1080 jpeg image of the selected "slice" of the light field can be exported. As of now, Living Imaging can be published three ways: by uploading to your own gallery on the Lytro website, embedding a Living Image window using HTML, or sharing on Facebook.

The Future

Since the first batch of Light Field cameras shipped in late 2011, the Lytro team has continued to improve the desktop software and camera's firmware. The latest Lytro camera firmware (v1.1.2) includes perspective-shift capability and manual exposure control, among other subtle tweaks. The Lytro-user community requested a self-timer—the Lytro support team delivered within weeks. Light Field pioneers raised concern over the camera's dynamic range—the Lytro support team developed an ND filter update. Last week, the desktop software alerted me of another update: a touch-activated magnification indicator that floats just under the zoom slider. Lytro's helpful and responsive support team is a selling point in itself.
As soon as Lytro releases an API or software development kit, LOOK OUT! The open source community and Lytro forums will abound with uploadable patches and alternate GUIs that surely will catapult Light Field pioneers deep into the frontier. Camera functions such as a remote shutter release capability or intervalometer may trickle in at first, followed immediately by a surge of metering modes, shooting modes, image manipulation tools and more. On the desktop software front, I look forward to 3D interpolation, animated GIF generator, focus stacking, depth mapping, and more functionality than my shallow focus can resolve.
By the time light field photography has evolved into a venerable creative medium, the torrent of media created by the intrepid pioneers may inspire new ways that we all interact with digital images. I'm thinking of hands-free, real-time dynamic focusing that is driven by eye-tracking software; in time, the Living Motion Picture that is focused entirely in post production.

The Bottom Line            

Light Field Technology available at a consumer-level price is a quantum leap for digital photography. As an imaging platform, the Lytro camera has a long way to go and its functions are sure to be refined. However, the ingenuity and potential built into Light Field Technology is undeniable—and revolutionary.
I admit being skeptical of the Lytro camera. I was ready to give this "fad-cam" a panning for the ages. But I cannot argue with results. Light Field Photography is not a fad, gimmick, reinvented wheel or any other derogatory term usually associated with the techno-schlockery that angry fanboys devour for sustenance.
Outlining ways that a point-and-shoot or DSLR camera outperforms the Lytro is as misguided as comparing apples to oranges plutonium.
Initially, I was dissuaded by the underwhelming 1.2MP (1080 x 1080) resolution of exported jpegs and the, at times, wonktastic user experience. Then I shifted focus from the pixel count and interface to the Lytro’s bigger picture. The Lytro will almost certainly be hailed as the device that ushered prospectors into the Light Field frontier. However, a failure to balance their forward-thinking design priorities with the practical needs of everyday photographers may halt Lytro’s Light Field expedition before it reaches the vanguard.
Incremental advances in material science and nano-scale engineering may help to silence some of the loudly voiced criticisms related to the Lytro’s image quality. A multicoated low-dispersion glass MLA would probably improve image quality in addition to low-light performance and spatial resolution. Moreover, the sooner the Lytro is "cracked" for open source development, the faster we all shall proceed into the uncharted lands of the light field frontier.
The Lytro camera has many strengths and innovative features previously unavailable to the consumer market. The combination of a stout metal housing, touchscreen interface, and steadily improving firmware and desktop software make the initial offering from Lytro very promising. Years from now, you may be reading B&H’s InDepth hands-on review of the LytroPRO Light Field Camera, perhaps a rubber-armored magnesium dodecahedron equipped with a large format light field sensor and a beast of an image processor. Until then, have a long and prosperous journey, Light Field Pioneers.

	16GB	8GB
Light Field Resolution	11 Megarays	11 Megarays
Sensor Type	Light Field	Light Field
Sensor Size	6.5 x 4.5mm	6.5 x 4.5mm
Aspect Ratio	3:2	3:2
File Format	Light Field  Picture File (.lfp)	Light Field  Picture File (.lfp)
Storage Type	Internal Flash Drive	Internal Flash Drive
Storage Capacity	16GB	8GB
Photo Capacity	750	350
Aperture	f/2.0 (fixed)	f/2.0 (fixed)
Focal Length (35mm equivalent)	35 - 300mm	35 - 300mm
Optical Zoom	8x	8x
Digital Zoom	none	none
Exposure Modes	Everyday; Creative (Shutter Priority, ISO Priority, Manual)	Everyday; Creative (Shutter Priority, ISO Priority, Manual)
Exposure Lock	Yes	Yes
ND Filter	Yes	Yes
Shutter Speed	8 - 1/125 sec	8 - 1/125 sec
ISO Sensitivity	80 - 3200	80 - 3200
Display	1.52" LCD touchscreen	1.52" LCD touchscreen
Computer Connectivity	Micro-USB	Micro-USB
System Requirements	Mac OSX 10.6.6 or later; Windows 7 (64-bit), Windows 8 (64-bit)	Mac OSX 10.6.6 or later; Windows 7 (64-bit), Windows 8 (64-bit)
Power Supply	Rechargeable Lithium-Ion Battery Pack	Rechargeable Lithium-Ion Battery Pack
Dimensions	4.4 x 1.6 x 1.6" (112 x 41 x 41mm)	4.4 x 1.6 x 1.6" (112 x 41 x 41mm)
Weight	7.5 oz (214 g)	7.5 oz (214 g)

One-point perspective

One-point perspective exists when the painting plate (also known as the picture plane) is parallel to two axes of a rectilinear (or Cartesian) scene – a scene which is composed entirely of linear elements that intersect only at right angles. If one axis is parallel with the picture plane, then all elements are either parallel to the painting plate (either horizontally or vertically) or perpendicular to it. All elements that are parallel to the painting plate are drawn as parallel lines. All elements that are perpendicular to the painting plate converge at a single point (a vanishing point) on the horizon.

Two-point perspective

Two-Point Perspective.

Walls in 2-pt perspective.
Walls converge towards 2 vanishing points.
All vertical beams are parallel.
Model by "The Great One" from 3D Warehouse.
Rendered in SketchUp.

A drawing has two-point perspective when it contains two vanishing points on the horizon line. In an illustration, these vanishing points can be placed arbitrarily along the horizon. Two-point perspective can be used to draw the same objects as one-point perspective, rotated: looking at the corner of a house, or looking at two forked roads shrink into the distance, for example. One point represents one set of parallel lines, the other point represents the other. Looking at a house from the corner, one wall would recede towards one vanishing point, the other wall would recede towards the opposite vanishing point.

Two-point perspective exists when the painting plate is parallel to a Cartesian scene in one axis (usually the z-axis) but not to the other two axes. If the scene being viewed consists solely of a cylinder sitting on a horizontal plane, no difference exists in the image of the cylinder between a one-point and two-point perspective.

Two-point perspective has one set of lines parallel to the picture plane and two sets oblique to it. Parallel lines oblique to the picture plane converge to a vanishing point,which means that this set-up will require two vanishing points.

Three-point perspective

Three-Point Perspective

Three-point perspective rendered using IRender nXt from computer model by "Noel" from Google 3D Warehouse.

Three-point perspective is usually used for buildings seen from above (or below). In addition to the two vanishing points from before, one for each wall, there is now one for how those walls recede into the ground. This third vanishing point will be below the ground. Looking up at a tall building is another common example of the third vanishing point. This time the third vanishing point is high in space.

Three-point perspective exists when the perspective is a view of a Cartesian scene where the picture plane is not parallel to any of the scene's three axes. Each of the three vanishing points corresponds with one of the three axes of the scene. One-point, two-point, and three-point perspectives appear to embody different forms of calculated perspective. The methods required to generate these perspectives by hand are different. Mathematically, however, all three are identical: The difference is simply in the relative orientation of the rectilinear scene to the viewer.

Four-point perspective

Four-point perspective, also called infinite-point perspective, is the curvilinear variant of two-point perspective. As the result when made into an infinite point version (i.e. when the amount of vanishing points exceeds the minimum amount required), a four point perspective image becomes a panorama that can go to a 360 degree view and beyond – when going beyond the 360 degree view the artist might depict an "impossible" room as the artist might depict something new when it's supposed to show part of what already exists within those 360 degrees. This elongated frame can be used both horizontally and vertically and when used vertically can be described as an image that depicts both a worm's- and bird's-eye view of a scene at the same time.

Like all other foreshortened variants of perspective (respectively one- to six-point perspective), it starts off with a horizon line, followed by four equally spaced vanishing points to delineate four vertical lines.

The vanishing points made to create the curvilinear orthogonals are thus made ad hoc on the four vertical lines placed on the opposite side of the horizon line. The only dimension not foreshortened in this type of perspective is the rectilinear and parallel lines perpendicular to the horizon line – similar to the vertical lines used in two-point perspective.

Zero-point perspective

Because vanishing points exist only when parallel lines are present in the scene, a perspective with no vanishing points ("zero-point" perspective) occurs if the viewer is observing a non-rectilinear scene. The most common example of a nonlinear scene is a natural scene (e.g., a mountain range) which frequently does not contain any parallel lines. A perspective without vanishing points can still create a sense of depth.

Other varieties of linear perspectiveOne-point, two-point, and three-point perspective are dependent on the structure of the scene being viewed. These only exist for strict Cartesian (rectilinear) scenes. By inserting into a Cartesian scene a set of parallel lines that are not parallel to any of the three axes of the scene, a new distinct vanishing point is created. Therefore, it is possible to have an infinite-point perspective if the scene being viewed is not a Cartesian scene but instead consists of infinite pairs of parallel lines, where each pair is not parallel to any other pair. Zero point perspective view is also known as elevation of any object