Projector Features Guide Projector Features Guide
Projector Features

There's such a wide choice of projectors available, we thought you might need some help working out which is best for you. So here's a guide to the features you should look out for.


Brightness
Resolution
Contrast Ratio
Weight
Data and Video Inputs
Audio Support (Speakers)
Keystone Correction
Lens Shift
Document Camera
Lamp hours (half life)
LCD or DLP?
Price!


 Brightness


Brightness is becoming less important as projectors get more advanced.

It's measured in 'ANSI lumens'. Most projectors released in the last year are around 3000 lumens or above, which is more than adequate for the average board room seating about 20 people. Brightness is much less important for home cinema as there is an overriding assumption that the projector will be used in a darkened room.


However if you are looking to buy a business or educational use projector, if there is a lot of ambient light and you don't want to have to darken the environment (or if you have a larger audience), you may opt to go for something between 4000 and 6000 lumens. However, expect to pay a bit more for this luxury!


We have a detailed Projector Brightness Guide and an easy to use Projector Brightness Calculator


 Resolution


The resolution is the accuracy of the image that the projector casts. Most business/educational use projectors fall into two categories - SVGA (800 x 600 pixels) or XGA (1024 x 768 pixels) but with High Definition sources such as Blu ray players and the latest PC's and laptops, FullHD 1080p (1920 x 1080 pixels) resolution is becomming more and more popular. Most computers and laptops output a signal which is either XGA or WXGA(1280 x 800 pixels) but have the abilty to display a higher resolution if selected in its settings ( limited by the graphic card). To get the best possible image it is vital you match the output resolution of your source to the native resoltuion of the projector.


Home cinema users - please note dedicated home cinema projectors project a native 16:9 (widescreen) image and fall into one of two resolution categories - 720p (1280 x 720 pixels) or 1080p (1920 x 1080 pixels).


If you use a PC, you can check which signal you're using. Go to Control Panel and select 'Display', then click the Settings tab. Next to 'Screen Area' you'll see a slider which shows what resolution you're using. If it's 800x600, you use SVGA. If it's 1024x768, you use XGA, 1280 x 800 you use WXGA. You can move this slider and press 'OK' to see the difference between the resolutions.


If you use a Mac, you can check which signal you are using by going to the 'Monitors' or 'Monitors and Sound' control pannel (depending on which Mac OS version you are using).

Most business projectors sold today are XGA resolution. This is because most computers sold today use XGA resolution or higher as standard. You can project an SVGA output signal with an XGA projector without significant loss of quality. However, projecting an XGA signal with an SVGA projector can make your presentation look unsightly.



See our feature about projector resolution for further information on this topic.


 Contrast ratio


If you're concerned about picture quality, don't just look at brightness. Contrast is just as important. In short, it's a measure of how well the projector can block out light from the lamp, ie. how black is the black? This is especially important for home cinema applications.

An average contrast ratio for business or education projectors is about 2000:1 for LCD projectors, whilst DLP projectors have contrast ratio of 3000:1.


See our features on LCD VS DLP for further information on the difference between the two display types.

 Weight


Are you taking your projector on the road or leaving it in the board room? If you are on the move, you'll appreciate having a projector that's as portable as you can afford. Thankfully, today's projectors are smaller than ever, with the lightest at around 1.1kgs and easy to carry over the shoulder. However, the desktop models still have more features and represent better value if the projector is going to stay in one place.



 Data and video inputs


You may want to project from a Satellite/Cable or Freeview box, DVD player or games console as well as a computer, or have all the sources connected and interchange between them. If this is the case, check how many data and video inputs the projector has.

If you want to project only video images or set up your own home cinema, have a look at our Home Cinema category. Here you will find dedicated home cinema projectors, which project in a native 16:9 (widescreen) aspect ratio.

See our cables and connections guide for more information on the different types of cables available.



 Audio Support (Speakers)


If you're likely to be projecting multimedia with sound, you can either connect your PC or video source to an amplifier, or if this is too much bother you can use the internal speakers (N.B. note an option on all makes and models). 6 watt mono is about standard for most projectors, as they are primarily display devices. This is enough for a room of 20 or 30 people if the only audio is speech. If you want something a bit more impactful, either look for a projector with at least a 10 watt speaker, or consider the amplifier option.



 Keystone Correction


'Keystoning' is the name given to the effect on the projected image when the projector sits below or above the centre of the screen. Keystone correction counteracts this effect by digitally compressing the image at the bottom or top, resulting in a squarer, more professional image.



 Lens Shift


Lens shift is generally a feature of high-end projectors or specialist home cinema models. Lens shift has a simular effect effect to 'Keystone correction' except that the effect is achieved by physically adjusting the angle of the projectors lens to square up the image. This is a better method of producing a square image, rather than using keystone correction as the correction with lens shift is acheived optically (rather than digitally) resulting in no loss of quality

Lens shift can also be useful for fine-tuning the position of the projected image on your screen.


 Lamp Hours (Half life)


A standard lamp lasts for about 3000 hours of projecting. That's a lot of presentations, and with lamps sold ranging from £150 to £500, it works out at between 5p and 16p per hour of use. Projectors with higher lamp half lives are less likely to cause you a problem in the middle of a presentation when the projector gets older and used more, and generally represent better value per hour of use. However, with all projectors a sharp knock can put the lamp out of action no matter how old it is. Environmental factors can also effect lamp life so it's prudent to have a spare on hand.


 LCD or DLP?


Until a few years ago projectors were mostly based on LCD technology, where the light from the lamp was filtered through red, blue and green LCD panels to produce a full colour image. Having three panels means that the projector casing needs to accommodate more room for the electronics, making the projector larger.

Then Texas Instruments developed DLP technology. DLP converts light straight into a full colour image, allowing manufacturers to make much smaller projectors. The downside is that the accuracy of the colours produced is not as accurate as many LCD projectors, so greens can look quite close to yellows, etc. If colour accuracy is really important to you, we suggest going for an LCD projector. More on LCD vs DLP >>


 Price!


Obviously you'd prefer to get your projector as cheaply as possible! Generally XGA adds about 30 per cent to the price of a projector with SVGA resolution, while brightness and portability are the other major factors. Weigh up the features you need before buying to get the best value!




Still confused? Then why not just give us a call. We'll ask you a little about what you want to do with your projector, and recommend exactly the right model for you.