Frequently
Asked Questions about Digital Projectors
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Q
Why
do I want a projector?
A To demonstrate computer programs, digital images,
share audio visual sequences with a large group of people
To give PowerPoint presentations
To be able to show video on a large screen. |
Q
How does a projector connect to my computer?
A: A projector connects to the computer and/or video
and projects the image directly onto a screen. There
are two types: video only and video/data.
Video projectors can effectively turn a large room into
a cinema, producing clear images up to 150" wide.
However, this type of projector cannot be connected
to a PC and receive a digital output signal. Data projectors
accept both video and computer digital output signals,
and can provide large-screen displays with much higher
resolution. |
Q
How much will a projector cost?
A: Anything between £1000 - £5000. Please
be aware that prices change constantly.
To purchase a projector that will meet AV needs would
be about £2000. (Again check & shop around).There
are hundreds of models on the market, so it is important
to get good independent advice about which model would
most suit your needs. You might consider ex-demonstration
projectors if your budget is limited. |
Q
Why should I want to buy an expensive model?
A The more expensive models give excellent picture quality
in most light conditions. They can be used for video
as well as data projection and can be easily connected
to different computers. |
Q
What are ANSI lumens?
A ANSI stands for American National Standards Institute
& ANSI lumens are the accepted standard measurement
of brightness for projectors. This is an important consideration
when choosing your projector.
If you are going to use the projector in a sunny bright
room you will need around 1000 ANSI lumens minimum.
Cheaper projectors (those with lower ANSI lumen ratings)
do not perform well when there is direct sunlight.
Where good blackout conditions are available, cheaper
projectors can provide sufficiently bright images. It
is recommended that you purchase a projector with a
minimum of 1000 ANSI lumens.
If you wish to use your projector in a large l hall,
consider 1400 ANSI lumens as a standard but you should
probably ask for an on-site demonstration to ensure
the projector meets your needs. |
Q
What kind of bulbs are there?
A There are two types of bulbs, halogen and metal halide.
Halogen bulbs are a light source used by certain, cheaper
LCD projectors. They produce a slightly yellow image
although you would have to compare it side by side to
notice a considerable difference. Halogen bulbs have
a considerably shorter life than the metal halide alternative
but are also cheaper to replace.
Metal halide bulbs are very bright and a long lasting
light source. They have a bluish white colouration characteristic
and are the accepted standard light source for 95% of
LCD projectors. |
Q
How much do bulbs cost?
A Prices vary considerably. Cheaper projectors (with
low ANSI lumen ratings) use 300w OHP halogen lamps,
which cost less than £20 but give only 75 - 125
hours of use. A 750w metal halide bulb can cost between
£250 & £350 but last 2000 hours. Higher
specification bulbs can last up to 6000 hours. It can
be a false economy to use cheaper halogen replacement
bulbs. Some have found that bulbs have failed quickly
and repeatedly. Investigations suggest that air filters
are clogging, resulting in heat build up, which subsequently
shortens bulb life. Clean the filters regularly to avoid.
Bulbs are at their most vulnerable when they are hot.
Always make sure they are cool before trying to move
the projector. Once the bulb has been switched off,
the projector must remain powered in up order for the
fan to cool down the lamp. Failure to do this before
moving the projector can shorten the bulbs life. Some
manufacturers recommend leaving the projector switched
on for an additional 5 minutes after switching off the
lamp. |
Q
What does resolution mean?
A Resolution measures the amount of detail that can
be seen in an image. For computers, resolution is expressed
in the number of pixels across and down the screen.
VGA requires 640 x 480 resolution, S-VGA 800 x 600,
XGA 1024 x 768. S-VGA should be the minimum resolution
for class use. |
Q
Do projectors have their own sound?
A Most projectors have a sound system, but the quality
can vary. Cheaper projectors tend to have a low sound
output and use built-in speakers (typically mono.).
The more expensive models will have higher sound output
and be stereo. These models will typically be strong
enough to use on their own in the class or small hall.
With all models it is easy enough to plug in external
computer speakers to increase the sound output for use
with large groups. |
Q
Will I be able to move it easily?
A It is important to consider weight if it is to be
used in several locations. As a rough.guide, a 2.9kg
projector is very portable, 4.5kg is manageable and
a 6kg can be moved but is probably best left in one
place. Some projectors can be purchased in a lockable/portable
cabinet and come complete with video and large castors,
easy to move from room to room and just plug in. However,
very small and light projectors sometimes produce poorer-quality
images, so it is important to balance portability with
brightness/image quality. |
Q
What do they stand on?
A You can use the normal projector stand or a table..
If the projector is to be ceiling mounted, there will
be additional costs for brackets and fitting. Health
and safety regulations often require a ceiling-mounted
power point too. |
Q
Where can I purchase a projector?
A When looking for a projector you should try to get
information from a company which deals with a wide range
of manufacturers rather than being tied into one single
brand. |
| How
to choose a projector website guidance from a projector
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| View
projector throw distance calculation tool by Epson |
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