conventional focusing or any adjustable
exposure parameters.
The camera is relatively easy to operate
(see the explanatory video on this issue’s free
DVD), although the narrow angle of view of
the LCD display does make using it quite
tricky, and if your shooting position means
that you have to view the screen from an
angle, you will basically be shooting blind.
You can view your captured images and
change the focus setting in-camera, although
the tiny size of the display makes the results
pretty unspectacular.
Viewing light field images on a computer is
an entirely different ball game. As soon as you
connect the Lytro to a Mac using the USB cable
provided, the camera automatically imports
your images. Downloading our 165 test
images took 13 minutes. Once your images
have been transferred, all you have to do is
select one from the overview in the supplied
software and click on the image detail where
you would like to place the center of focus. The
software then automatically generates and
displays the appropriate two-dimensional
image. Changes in focus take place steplessly
and independently of the optical
characteristics of the lens itself.The resulting
planes of focus and blur are similar to those
produced by a standard lens at its widest
aperture setting and have a convincing
photographic look. The focus shift effect is
really quite spectacular when viewed on a
large monitor, although Lytro doesn’t let on
exactly how its software works.
Each captured image takes up about 20
megabytes of memory and has a quoted
resolution of 11 megarays, which means that
it contains data relating to the direction,
intensity and color of 11 million separate light
rays. These numbers indicate that the
production Lytro contains technology that is
a lot more sophisticated than that described
by Ren Ng in his dissertation.
The company calls the images the device
produces “living pictures”, and the way you
can adjust the point of focus within an image
just by clicking on it is truly amazing. Light
field images are great for use with interactive
online or computer-based media, but their
meager 1080x1080-pixel (1.2 MB) resolution
isn’t sufficient to produce usable prints.
You have to choose your subject carefully
if you want to make the most of the light field
effect, and most smartphones are more suited
to general, everyday photography. The effect
only really becomes visible if the subject has
sufficient depth of detail to provide multiple
effective points of focus. If you don’t take such
compositional factors into account while
shooting, the Lytro cannot exploit its special
capabilities to the full.
The Hardware
The Lytro’s manufacturer keeps much of the
device’s technical data secret. What we do
know is that the built-in zoom lens has a
fixed aperture of f2 and that an array of
microlenses – which scans and captures the
direction the incoming light comes from – is
positioned between the lens and the sensor
chip. Lytro doesn’t give away any information
about the sensor resolution or the exposure
parameters the camera uses, but we can safely
assume that the sensor’s resolution is at least
11 times that of the resolution of the resulting
images. The metadata displayed in the viewer
software includes shooting mode, aperture,
focal length and the automatically selected
exposure time and ISO values.
The Lytro also has a built-in Marvell Avastar
88 W8787 WiFi and Bluetooth chip, although
these capabilities are not activated in the
current version of its firmware (see the FCC
report at http://goo.gl/Bo2nN). Wireless
technology would make all sorts of new
applications of light field technology possible,
such as a streamed image link to a mobile
telephone. The image sensor is a 6.5x4.5 mmmodel of unknown manufacture, and each
microlens appears to steer incoming light
towards 10 separate sensor pixels. The camera
also contains a Zoran ZR 364 246 BGXX
processor, but Lytro doesn’t provide any
details about its intended use.Not Yet Perfect
In spite of its fascinating built-in capabilities,
the Lytro still has some obvious drawbacks.
The Lytro image format is unique and
proprietary, and doesn’t give you any real
control of the shooting parameters it uses.
The range of available ISO values is quite
narrow and the touchscreen monitor/control
panel is too small with too narrow a usable
angle of view. The usable resolution of the
captured images isn’t sufficient to provide
adequate print quality over the entire range
from macro to telephoto. Less important, but
nevertheless limiting is the absence of a tripod
thread, a self-timer and built-in flash.
The lack of a Windows version of the Lytro
software is a serious shortcoming and, if you
want to publish light field images on the
Internet, you have to upload them to the LytroLight Field Photography | The LytroLYTRO LIGHT FIELD CAMERA DATA
Manufacturer Lytro, USA / http://www.lytro.com
Equivalent focal length 43-350 mm^1
Aperture / Zoom range / Min. macro distancef/2 (fixed) / 8x (optical) / 45 mm
Exposure control / Zoom – / manual via touch pad
Image sensor / Resolution 6.5x4.5 mm^2 / 11 megarays
Image resolution 1080 x1080 pixels
Modes Everyday (adjustable exposure), Creative (adjustable focus)
Output format Camera: Light Field Picture (.lfp), software image export: JPEG
Flash / Tripod thread – / –
Power supply 3.7 V, 2100 mAh Li-Ion battery
Memory Built-in 8/16 GB flash (350/750 images)
Display LCD touchscreen, 38.55 mm (1.52") diagonal, 26x27 mm
Computer interface Micro USB 2.0
Software For image import, focus adjustment and JPEG export for Mac OS X (10.6.6 and later)
Dimensions (WxHxD) / Weight 41 x 41 x112 mm / 214 g
Price US$399 (8 GB model), US$499 (16 GB model) plus delivery(^1) measured optically (^2) according to the FCC –ˇnot included
The top-of-the-range model
from Raytrix delivers light
field images with an
effective resolution of more
than seven megapixels