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
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 since the millennium are around 1000 lumens or above, which is more than adequate for the average board room seating about 20 people. However, if there is a lot of ambient light and you don't want to have to draw the curtains (or if you have a larger audience), you may opt to go for something nearer 2000 lumens. However, expect to pay a bit more for this luxury!

Resolution

The resolution is the accuracy of the image that the projector casts. Most projectors fall into two categories - SVGA (800 x 600 pixels) or XGA (1024 x 768 pixels). Similarly, most computers output a signal which is either SVGA or XGA.

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. You can move this slider and press 'OK' to see the difference between the resolutions.

Most projectors sold today are XGA. This is because most computers sold today are moving to XGA resolution 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 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 clarity of text, and in home cinema applications.

An average contrast ratio is about 400:1. Some projectors have contrast around 800:1.

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 1.5kgs 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 video player as well as a computer, or have both connected and interchange between the two. If this is the case, check how many data and video inputs the projector has.

Audio Support (Speakers)

If you're likely to be projecting multimedia with sound, you can either connect your projector to an amplifier, or if this is too much bother you can use the internal speakers. 1 watt mono is about standard for most projectors. It may not sound like much, but it's 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 a 2.5 - 3 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 stretching the image at the bottom or top, resulting in a squarer, more professional image.

Document Camera

A few projectors, mostly in the Toshiba range, have inbuilt digital cameras that output images directly into the projector. This is useful if you have documents that you want to show your audience, but don't have time to scan them in and add them to your presentation.

Lamp Hours (Half life)

A standard lamp lasts for about 2000 hours of projecting. That's a lot of presentations, and with lamps sold at £200-400, it works out at under 20p 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, 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 yellow 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 a slightly bigger 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 to 40 per cent to the price of a projector, 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.