Audio Visual Frequently Asked Questions
Whats the difference between LCD and DLP projectors?
LCD projectors form images by shining light through one or three LCD
panels. Generally, LCD projectors are larger and heavier but, have better image quality.
LCD is a proven projection technology that produces bright, high-resolution images.
Digital Light Processing (DLP) technology is an optical system driven by digital electronics.
The heart of the digital projection process is a thumbnail size semiconductor switch consisting
of microscopic mirrors. Because DLP is a reflective technology, it has many
advantages over analog LCD and CRT systems, principally greater light efficiency. This means
brighter, more life-like images and colours and sharper details however,
colour saturation and center to edge brightness uniformity tend not to be quite as good as LCD.
Contrast ratio, tends to be a strong point of DLP projectors.
Which display technology should I use, LCD or DLP?
If you are projecting a presentation, such as Powerpoint, that incorporates large fonts and bright colours,
LCD may look better. If you are showing small fonts, more detailed or higher contrast
images (or you are looking for an ultra lightweight projector), DLP may be preferable. If video
is your application, look carefully at both; you will find a range of video quality in both DLP
and LCD projectors.
Are iLink and Firewire the same thing?
Yes. Some camcorder manufacturers, such as Sony, refer to Firewire. The base standard
is actually IEEE-1394 serial bus.
What does resolution mean?
Resolution refers to the number of horozontal scan lines recorded by a camcorder or
displayed on a television.
For a computer display monitor resolution specifies the number of pixels across and the number
of pixels down.
What does MPEG stand for?
The Motion Pictures Expert Group (MPEG) is an international organization which specifies the
standards for video encoding (compression).
- MPEG-4 is a relatively new standard which delivers better video quality for lower data
transfer rates. Presently support for the standard is weak.
What digital video (DV) formats are there?
- MiniDV (tape)
- Digital 8 (tape) The DV signal is recorded on a Hi8 tape.
- MicroMV (tape) An MPEG-2 data stream is recorded on a small videotape.
- DVD-R/DVD-RAM (disc) DV is recorded onto a DVD disc with DVD-R being once only and DVD-RAM
capable of up to 100,000 rewrites.
Does the Charged Coupled Device (CCD) capture the picture?
Yes. The CCD converts the light entering through the lens into a compressed digital stream.
More than one CCD can be used to provide higher quality images.
How does image stabilization work?
There are two types of image stabilization available to reduce the shaking of a handheld
- Digital Image Stabilization - this is the most common form of stabilization and is
achieved by "floating" the image on the CCD and moving it in the opposite direction to the
- Optical Image Stabilization - is a more sophisticated (and expensive) method of stabilization
achieved by mechnaically moving the lens elements.
What is Backlight Compensation?
A white balance s required by camcorders to compensate for different colour temperatures of
light sources. An incorrect compensation setting can give unattractive tinting of image colours.
What are the advantages of digital video?
- more compact camcorders
- improved resolution (twice VHS), colour and sound quality
- transfer to computer of an exact copy at high speed
What digital video sources can I use?
Any digital video source can be used including laptops, notebooks, media tablet PCs, smartphones and even GPS Navigators as long as
there is a suitable connection available and the video file is compatible with those supported by the projector.