About HD Projectors
With such a wide range of HD projectors available it’s important you know what to look for and consider before purchasing an HD projector. For advice on the home cinema HD projector see our dedicated article. Below we list some of the most important features and qualities to look for in your hd projector:
HD Projector Brightness
The brightness quality of you hd projector is a less important factor than it used to be as hd projectors become more advanced
Brightness of projectors is measured in ANSI lumens. Most projectors currently available will have an ANSI value around 1500 lumens or above which is more than sufficient for a large room of people (20+). Brightness only really matters if the hd projector is going to be used in a bright room however most people setting up a home cinema will be watching the tv / film in a dark room and this is more than adequate. However you may need a projector between 2000 and 3000 lumens if this is not the case although expect to pay more for this extra.
Resolution can be considered the accuracy of the image projected by the hd projector. Most current hd projectors will be either – SVGA (800×600) or XGA (1024×768) pixels.
However for specific home cinema projectors the majority will be projecting a native 16:9 (widescreen) picture and therefore are either – WVGA (854 x 480 pixels), WSVGA (1024 x 576 pixels) or WXGA (1280 x 720 pixels). The ‘W’ stands for ‘Wide’.
Along with brightness contrast is just as important for good picture quality. Contrast is expressed as the measure of how well the projector blocks light therefore how black, black really is which can be particularly important for home cinemas.
Contrast ratios vary although LCD projectors are usually 400:1 while DLP projectors can reach 4000:1 contrast ratio.
This is an important factor to take into consideration depending on whether the HD projector will be portable or setup permanently in a home cinema environment. Projectors are now smaller than eve and the lightest can be less the a kilo. Check the hd projectors before you buy and you may find it easier to put up!
Keystoning occurs when an hd projector is sitting above or below the centre of the projection screen. With inbuilt keystone correction the effect is corrected by digitally compressing the image at the bottom or top to give the presented image a squarer expected picture.
With lens shift the user is able to phyiscally adjust the lens angle to counteract the similar effect to key stoning. Lens shift is usually only available in top end home cinema projectors but is a better method for producing square images as it is physically manipulated instead of digitally which leads to quality loss. Lens shift also allows you to fine tune the projected image to a precise location on screen.
The typical projector lamp can be expected to last around 2000 hours use. Lamps are generally available new between £150 and £500 which therefore represents and hourly use of between 8 – 25p. Lamps with a longer life will give better value for money however at the end of the day any sharp knock to a lamp can finish it so care is a must or at least a have a spare on standby.
Projectors were only available in LCD form until a few years ago. This meant light from the lamp was filtered through a red, blue and yellow LCD panel to produce the full projected image. With the need for three individual colour panels projector cases were generally larger to accomodate all the extra electrics.
Texas Instruments have since developed DLP technology. With DLP technology the light projected is immediatley converted to a picture saving alot of space. However this technologies downside is that the overall colour produced is not of the same accuracy as LCD. This is only a real issue if colour accuracy is of high importance.