We initially covered aspect ratios back in the section Resolutions and
Aspect
Ratios Explained In this section, we will go in-depth about how projectors
display different aspect ratios.
Scenario One. You are going to buy a widescreen projector and would like to know
what to expect when using it to view non-native aspect ratios.
The first thing to understand when purchasing a widescreen home theater projector
is that almost no content is actually in a 16:9 (1.78:1) aspect ratio. Therefore,
almost all of the material you watch will be formatted to fit onto your screen
(with black bars displayed on top and bottom or on the left and right of the image).
When watching standard definition television (4:3 or 1.33:1 aspect ratio material),
you generally have the option of either watching the material in its native aspect
ratio or stretching the image. Most home theater projectors will usually give the
option of blowing up the image to fill the entire screen, thus cutting off some
of the top and bottom of the image, or subtly stretching the image horizontally.
And, both options have serious flaws: either you'll chop off some of the image
or you'll stretch the image and cause image distortion. The best option is to
leave the image alone.
Example 1 shows the difference between stretching the image horizontally versus
leaving the signal as a 4:3 image.
Example 1
Watching DVDs, or other material that is film-based, will result in your
discovering that movies are seldom, if ever, filmed in a 16:9 (1.78:1) aspect
ratio. Instead, they are generally recorded in a 1.85:1 or 2.35:1 aspect ratio,
which is actually wider than the aspect ratios of widescreen projectors or
televisions. When watching material in a 1.85:1 or 2.35:1 aspect ratio on your
widescreen projector, your image will look like example 2.
Example 2
Whenever a projector adds black bars to an image, you are no longer using the
full resolution of your projector. If buying a widescreen projector, make sure
to match the resolution of the projector to the resolution of the content you
will most likely watch to ensure the best results.
If you aren't watching HDTV often, and don't plan on converting to it in the
next few years, an 854 x 480 projector will suffice for watching standard
definition television and DVDs as it most closely matches the resolution of DVD.
If most of your viewing is DVD and standard definition television, and you do
watch some HDTV programming, a 1024 x 575 or 960 x 540 projector will give you
wonderful clarity for both standard definition and high definition sources.
If you love your HDTV now and want something that takes full advantage of it,
then a 1280 x 720 or greater resolution projector is what you need. But keep
in mind that standard definition sources will generally look crisper on a
projector that better matches its resolution.
Scenario Two. You are going to buy a 4:3 aspect ratio business projector to use
for home theater and would like to know what to expect when using it to view
non-native aspect ratios.
Mapping widescreen images onto a 4:3 projector can pose unique challenges and
a consumer needs to be aware of them.
Micro display projectors all have a native resolution that can't be changed.
If you are buying a 4:3 projector and plan to watch widescreen images on it,
you must understand that you are going to lose a significant amount of
vertical resolution in the process. Let's look at a native 4:3 aspect ratio
800 x 600 (SVGA) projector as an example.
If you watch a 16:9 (1.78:1) aspect ratio image on an SVGA projector, your
total vertical resolution available drops from 600 lines to 450 lines as
seen in Example 3.
Example 3
If you watch even wider screen images on an SVGA projector, your vertical
resolution drops even further. Example 4 shows a 2.35:1 image on an SVGA projector.
Example 4
Problems can arise when you try to watch HDTV images on a projector with too
low of a resolution. A 1280 x 720 image from a 720p HDTV signal would have
to be scaled down to 800 x 450 on an SVGA projector. That is a staggering 61%
loss of resolution! The situation would be worse when watching a 1080i HDTV signal.
Here is a quick table of the 16:9 (1.78:1) resolutions for common 4:3 aspect
ratio business projectors. Remember: always choose a projector that best
matches the resolution of the source material you watch the most.
An SVGA (800 x 600) projector is actually 800 x 450 when viewing a 16:9 image.
An XGA (1024 x 768) projector is actually 1024 x 575 when viewing a 16:9 image.
An SXGA (1365 x 1024) projector is actually 1365 x 766 when viewing a 16:9 image.
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