Share Your Still And Video Images With The Latest Digital
Projectors
By Ibarionex R. Perello
As photographers,
it’s a satisfying moment when we’ve snapped the shutter
and captured a fine photograph. It’s an even bigger thrill
when we share our vision. With today’s technology, sharing
our images has evolved beyond simply displaying slide after
slide in a carousel. Now, digital projectors display slideshows
complete with music, transitions, titles and special effects.
Whether it’s video from the latest vacation or a collection
of family portraits, you can create presentations that are both
beautiful and engaging.
With technological and manufacturing improvements, projectors
have become increasingly affordable. They not only serve as
a means for sharing images, but can become the heart of a home
entertainment system, bringing more significance to the term
“multimedia.”
There are many products from which to choose and numerous features
to consider when deciding which type of projector will best
suit your needs.
LCD
Vs. DLP
There are currently two technologies that comprise the majority
of digital projectors—LCD (liquid crystal display) and
DLP (Digital Light Processing). Each works on the principle
of converting light into individual pixels, but performs the
function in a different way. Both technologies have their advantages
and disadvantages, and understanding how you intend to use a
projector will guide your purchase decision.
LCD projectors create an image when light emitted from the internal
light source hits three separate LCD glass panels, consisting
of pixels that represent the three primary colors (red, green
and blue). The individual pixels are either turned on or off,
with “on” pixels passing light to the lens, which
projects the image.
LCD projectors are considered the top choice for achieving the
best color accuracy and saturation, yet they have a narrow contrast
ratio when compared to DLP projectors and are less effective
in producing crisp blacks. Recent models have improved the contrast
ratio, resulting in better gradation of tones, however. LCDs
are more light-efficient, producing greater brightness (ANSI
lumens) from the same wattage lamp. At lower resolutions (SVGA),
some projectors can show evidence of pixelization, but recent
advancements have made this less of an issue, even with very
affordable models.
Developed by Texas Instruments, DLP technology is designed around
an optical semiconductor known as a Digital Micromirror Device
(DMD). The DMD’s pixels consist of tiny individual-adjustable
mirrors that direct or deflect light from the light path leading
to the lens. The movement of the mirrors combined with the duration
during which they reflect light produces varying shades of gray
for a total range of 1,024. Color is achieved by a rapidly rotating
color wheel that’s positioned between the light source
and the DMD. To achieve a specific color, a pixel mirror becomes
active only when the appropriate segments of the color wheel
are being impacted by light.
On the high end, some DLP systems feature three chips (red,
green, blue) for rendering color, eliminating the need for the
color wheel and delivering improved color. These models come
at a premium price point, however.
DLP projectors offer a significantly higher contrast ratio (e.g.,
2,000:1 as compared to 400:1), which improves the projector’s
ability to render gradual transitions of tones between black
and white. The look produced by such projectors is favored by
many for displaying video. Professional DLP projectors are increasingly
finding their way into many movie theaters converting to digital
projection.
Due to their use of a color wheel to produce color, DLP projectors
tend not to provide as high color saturation. Also, the use
of the color wheel can result in a “rainbow effect”
for some viewers in which they become aware of the separation
of colors being produced by the color wheel’s rotation.
This problem has been reduced by increasing the rotation speed
of the color wheel and increasing the number of color panels.
A few still may experience the effect due to the sensitivity
of their eyes, however.
If your projector is used primarily for displaying your images
and you’re concerned with achieving optimal color accuracy,
you may prefer an LCD projector. If you work with video and
plan to incorporate the projector into your home entertainment
system, a DLP projector might be the better choice.
Brightness
Another consideration is the space in which you expect to use
the projector. Will you display your images in a small, dark
room or a brightly lit conference room? A projector’s brightness
is measured in ANSI lumens. Typically ranging from between 1,000
to 3,000 lumens, this rating determines the quality of the projected
image when it’s subject to ambient light, as well as increases
the distance that the projector can be from the screen and still
produce a strong image.
If you intend to project your images in a small room with little
to no illumination, a 1,000-lumen projector easily will produce
a good image on a screen less than 100 feet away. If you intend
to share your images with a large group under ambient or artificial
illumination, a projector with between 1,500 to 3,000 lumens
will be preferable.
The replaceable light sources promise hours of use, approximately
up to 2,000 hours in many cases. You should be aware that the
brightness produced by a projector is reduced as the light source
nears the end of its life. If brightness and image quality are
important and you intend to use the projector regularly, factor
in the cost of replacement light sources with your initial purchase.
Resolution
Resolution reflects the number of pixels used to create the
images projected on the screen. There are three native resolutions
offered in most of today’s projectors—SVGA (800 x
600), XGA (1024 x 768) and SXGA (1280 x 1024). Even today’s
lower-resolution displays will show little evidence of pixelization
at a normal viewing distance.
SVGA and XGA monitors make up the great majority of affordable
projectors. The lower-priced models often offer SVGA resolution,
although XGA models are common and are increasingly dropping
in price.
At a native resolution of 1024 x 768, XGA-resolution projectors
can render finer details without the telltale signs of pixelization.
It allows the projector to be farther away from the wall to
produce larger images that still maintain good detail. For photographers
who want the ability to project large magnifications of their
images and maintain good image quality, this resolution may
offer the best compromise of quality, image size and price.
SXGA-resolution projectors render amazing detail, but often
are more expensive and heavier. These models are likely to be
mounted permanently in an office or a home entertainment system.
Size And Weight
As brightness and image quality have steadily improved, the
size of projectors has become smaller and smaller. This trend
has been influenced largely by the demand of business users
who often travel with projectors, which they use in presentations.
Weights can vary from as light as 2.1 pounds to a hefty 10 pounds
or more. Moderate-sized projectors range in weight from between
four to six pounds. Sub-four-pound projectors are dominated
by DLP projectors, although a few models, including recent releases
announced by Epson, offer LCD projectors in this weight category.
If you intend to use the projector for business or simply to
tote it along when visiting family and friends, a compact projector
is well worth the increased cost. Otherwise, if the projector
is intended for a single location or is part of a home-entertainment
system, a heavier model will do fine.
Pricing
Once you’ve considered all the features, eventually it
comes down to how much you can expect to pay. Prices range anywhere
from $999 up to $14,000, but there’s a wide selection of
projectors that come at affordable price points where you don’t
have to sacrifice quality and features.
The best way to determine which model is best for you is to
decide which features you can’t do without, allowing you
to narrow the selection. We recommend that you visit your local
audiovisual or computer store for some hands-on comparisons.
Showing
Your Images
There’s a wide variety of ways to output your images to
a projector whether or not you choose to use a computer. All
projectors feature video connectivity in the form of a standard
RCA-video connection. Some models also may include S-video or
component video ports, which deliver improved video quality.
An increasing number of projectors are making it possible to
display a slideshow without a tethered computer. One way is
by the inclusion of a built-in card slot that will accept memory
cards (CompactFlash, Memory Stick, SD). The stored images then
will be projected on the screen automatically. The convenient
feature provides a quick and easy way of sharing presentations.
Utilizing the projector’s menu options, the images on the
card can be read and transmitted on the screen. JPEG rather
than RAW files will need to be on the card in order to be properly
displayed.
You also can connect your camera directly to the projector using
the camera’s output jack, which provides the ability to
project both RAW and JPEG files. However, this will be at the
low video resolution of 640 x 480.
If you’re using a computer, you may not need a cable to
connect your laptop to your computer. Many models now provide
wireless connectivity using an 802.11 standard for data transfer.
This also gives multiple users access to the projector. The
data transfer rate varies, depending on which generation of
wireless connectivity you’re using. If you intend to transmit
video, it’s highly recommended that your computer and projector
utilize the 802.11g standard, as it provides the highest data
transfer rate as compared to 802.11a and 802.11b.
A few recent models feature a built-in DVD player, which allows
for images that have been burned to disc to be projected.
