With such a large variety of projection systems on the market today, choosing the right one for your presentations can be a daunting task. The simplest place to start is by eliminating the projectors which are unsuitable for the job. For example if you use an XGA laptop or PC then choose an XGA projector. If you are a roaming presenter then choose a small, light projector. If you cannot plan for ambient light levels then get a projector bright enough to be flexible. This will immediately eliminate half of the machines you are looking at. Take a look at our articles page for further assistance.

Projectors, LCD/Plasma panels are pixel based displays. This means that - unlike CRT displays - they have a native resolution. Whilst the vast majority of these displays are capable of scaling non-native resolutions that are fed to them, it is generally best if you use the projectors native resolution. The current standard for business presentations is "XGA" or 1024*768 (the number of columns * lines) with "WXGA" (WideXGA) starting to make inroads as pricing drop. WideXGA is useful from the point of view that most modern laptops use widescreen monitors so the aspect ratio of a WXGA projector will match that of the laptop.

For a full list of standard resolutions see "Resolution" in our glossary.

HDTV (High Definition Television) is an emerging high resolution standard for television and DVD formats. There are 2 resolutions which can be defined as high definition, 1280*720 and 1920*1080, both in 16:9 widescreen aspect ratio.

In order to be defined as high definition ready, a display device (projector, plasma, lcd etc.) must meet the following criteria:

i. The device must physically have a minimum of 720 lines in wide aspect ratio.
ii. The device must be able to accept 1280 x 720p and 1920 x 1080i at 50 and 60Hz
iii. The DVI or HDMI input must support content protection (HDCP)

It is on point ii. that many devices fail. Although many devices support a native resolution of 1280*720 or more, some cannot accept a 720p or 1080i signal at 50Hz and require that the frequency be increased to 60Hz, which usually involves using a scaler. You should bear this in mind before you purchase.

The other point to keep in mind when purchasing your display is the native resolution. For example, although an a wide aspect ratio plasma or lcd screen may have a resolution of at least 720 lines, it's horizontal resolution may be less than 1280 columns. So, if you have a resolution of 1024*768, the high definition source will need to be scaled up vertically to 768 lines and scaled down horizontally to 1024 columns, so information will be lost.

HDReady displays will display the following logo, if not then check for compatibility first!

There are two common technologies and two rarer technologies used in home cinema projectors. The common ones are DLP (digital light processing) and LCD (liquid crystal display), the rarer CRT (cathode ray tube) and LCOS (liquid crystal on silicon) which are used on higher end projectors.

Traditionally LCD's strengths are in colour saturation and accuracy, efficiency and image sharpness. The better saturation gives a richer more vibrant look to the picture and colours are rendered more accurately. The better light efficiency means that for a gives lamp wattage, LCD projectors will tend to give more light than dlp. Image sharpness is near perfect with LCD (like the difference between and lcd monitor and a normal CRT monitor) whereas DLP has a slightly softer focus.

LCD's weakness lies in two area's. The most commented on is the "screendoor" or "chicken wire" effect whereby you can see the pixel structure. In modern LCD video projectors this is much reduced by using higher resolutions and Micro Lens Arrays (MLA) which reduce pixel visibility. LCD's other weakness is contrast ratio which means it cannot usually match DLP for colour detail or black levels.

DLP's strengths are two fold. The most obvious is contrast ratio, which in better machines can triple the best LCD can offer, giving a more television like picture. The second is pixellation. On higher resolution DLP machines the pixel structure becomes virtually impossible to see (a result of not being as perfectly focused as LCD which is an advantage for video viewing).

The weakness is the "rainbow effect" which is the common term for the colour seperation that can occur because DLP projectors rely on a spinning colour wheel made up of red, green and blue (and sometimes clear) filters. Because each colour is in effect being displayed seperately, some people can detect this seperation.

In the end, taste applies and you should audition each type of projector before you decide on which to purchase.

For a fuller explanation of DLP and LCD please ProjectorCentrals web site please click here.

This simple answer is a qualified yet. The vast majority of projectors support video as well as data, you’d have to look hard for one that doesn’t. The qualifies bit is more about quality then whether it can or can't. Most business projectors are optimized - both in their signal processing and brightness - for giving business presentations possibly in relatively high ambient light. This means that they will generally be too bright for home cinema use with controlled lighting. For a list of machines that may be suitable to you for both purposes see out home cinema list under "Projectors" and scroll to the second list "High Definition Ready Presentation Projectors".

In general, projectors up to about 3kg are easily portable (the average laptop is about 3kg). If you travel a lot with your presentations then try to stick to 3kg or under. If your presentations are more usually to clients visiting your organisation then the weight becomes less of a consideration as you’re unlikely to be lugging your entire kit around. Projectors over 8kg are generally best suited for fixed installations.

All presentation projectors (sometimes known as "Powerpoint Projectors") are supplied with the appropriate cable to connect to your PC. This will usually be either a VGA cable or - less commonly - a DVI cable. In order to get a picture this cable will need to run from the monitor output on your computer to the computer input on the projector. Note that on some laptops the monitor port will sometimes need to be switched on, usually press the Fn key and one of the function keys. See your computer documentation for more information.

Windows XP Minimize your running applications so the Windows desktop is displayed. Click the right mouse button and select "Properties" from the menu that appears. The "Display Properties" window will appear. Along the tabs at the top left click on "Settings". The currently selected resolution of your PC is displayed in the "Screen resolution" panel near the bottom. Note that in older versions of Windows this panel is labelled "Screen Area".

In this window you can also set the "colour depth" which is the number of colours which Windows uses.

Windows Vista Minimize your running applications so the Windows desktop is displayed. Click the right mouse button and select "Personalize" then left click "Display Settings". The window that appears wil show your resolution towards the bottom left.

Mac OSX - Click the Apple menu (top right), select "System Preferences" then click "Displays". The current resolution is highlighted.

Linux Gnome - One the desktop menu choose System -> Hardware -> Screen Resolution

Generally a matte white screen is fine with modern projectors unless you have unusual requirements. On our articles page you'll find detailed assistance which goes far beyond the scope of an FAQ on choosing a screen.

The brightness of projectors is measured in ANSI (American National Standards Institute) lumens. In general, the brighter the image a projector can produce, the more impact your presentation will have and the more amibient light the projector can cope with. For small groups of people in an office 1500-2000 lumens is fine, in a meeting with more than 20 people think of 2000-3000 and for presentations to large groups of people, go for a projector of over 3000 lumens. Bear in mind that the quality of the screen and the ambient light will have a dramatic effect on the image brightness. See our articles page for more extensive information.

All the equipment we supply is UK sourced and comes with a minimum 12 months parts & labour warranty. Most manufacturers supply 2-3 years and some - for instance Optoma, Epson and Mitsubishi - supply a hot swap warranty whereby you will be lent a projector whist yours is repaired or the projector will be swapped out permanently. Please note that the "loan support" warranties will be dependent on the manufacturer having stock of a similar model to lend you.

Most projectors are fitted with minimal audio capabilities (some sub micros and home cinema machines have none at all). The video leads, whether they are VGA or DVI do not carry audio so a separate cable is required. This is usually a small cable with 3.5mm stereo mini jack plugs. Connect this to the audio input on the projector and the line out (NOT the speaker socket) on your PC.

The best solution is to (at least whilst using the projector) alter the Windows resolution to match your projector.

If this is not possible then the projector will expand or compress the incoming signal to suit it’s native resolution. This is called scaling and works with varying degrees of success so if this is your only option then give your presentation a trial run before the main event!

Unlike CRT monitors, plasma screens, projectors and LCD screens have a fixed number of pixels, referred to as the “native resolution” and is the resolution at which the display device does not have to expand or compress the input signal. In other words, this is the resolution the device looks best at.

Computer display units, whether they are LCD monitors, projectors or plasma screens are pixel based displays. The resolution you use or your display supports is the number of pixel columns by pixel lines i.e. 1024*768 (XGA) is 1024 columns of pixels by 768 lines. It follows from this that the higher the resolution the smaller the pixels for a given screen size. The smaller and more numerous the pixels, the finer the detail which can be displayed.

This can be quite a concoluted question. You'll find information in "Choosing the Right Size" in out articles page but keep in mind that there are factors which may take you away from the ideal. For example, if you are a business presenter then the size may be limited to what you can carry with you. If you are setting up a home cinema then you may want to exactly cover a window.

Using VGA cable (the cable with 15 pin "D"shaped plugs) the usual maximum figure is around 15 metres with a good quality cable. This however can vary somewhat depending on the cable quality and external conditions so it’s as well to test before it becomes critical. If you experience problems then you may need a signal or distribution amplifier.

DVI is a little more limited. Cables up to 5-7 metres should work but anything longer may require a very good quality cable or boosting.

See also:
Computer / Component - Distribution and DVI & HDMI - Distribution Components on our products page.

At the moment, the term high definition encompasses two different resolutions 720 (1280*720) and 1080 (1920*1080). In order to differentiate the higher resolution products, some manufacturers use the term "TrueHD" or "True HDReady" for display devices with a resolution of 1920*1080 or higher.

Trying to find the right projector for your home can very quickly get very confusing. There are so many out there, each making claims of excellence and so many reviews that seem to contradict each other that making a choice can seem impossible. Projector technology is fast moving (although not quite as fast as in the early days) so when is the right time to buy?

There are a few decisions you need to make which will help narrow the choice down:

• What is your budget?


• What image size would you like?


• What is your throw distance?


• What are your ambient light conditions like?

The first question is one only you can answer but we got advice and tools to help with the rest. In order to make things as clear as possible we've seperated to questions to their own question is the FAQ so to continue click here.

Selecting the right screen size is critical to your home cinema experience. If the screen is too small then you won't get the full cinema effect, if it's too large then it will be uncomfortable to watch. As a good starting place click on the articles page and select "Choosing the Right Size".

Often your selection may be limited by the room or the seating distance so treat advice as a guideline rather than rule and think about delaying the purchase of a screen. Most projectors will produce a perfectly watchable image on a light coloured wall so watch a film projected against a wall, adjusting the image size to your preference then measure the image produced. This will give you a good ide about what size screen you want.

If you know what size you want then you can quickly find screens which match using our screen-wizard.

The throw distance of your set-up is the distance from the front of the projector lens to the screen. In home cinema systems this is often dictated by where you can put the projector from which you can work out the throw ratio you will need. Say you have decided that you want a 2 metre wide image and you'll be putting your projector on a shelf at the back of the room 4 metres away from the screen. This gives you throw ratio of 2:1 (the distance to size ratio).

To find a list of projectors which will produce a given image size from a given throw distance try our Throw Finder.

If you know the image size and the projector you want then use our Throw Calculator.

Yes! Ambient light will have a very noticeable effect on your image no matter how good the projector, lens or rest of your kit. Try to keep ambient light to an absolute minimum to maximize the impact of the projected image. Remember that your screen reflects light from any source so the darkest it can get is with the ambient light subdued as much as possible. This "black level" has a direct effect on perceived contrast ratio.

In the tools section of our site you'll find the "Throw Finder" tool. (Note that if you are browsing www.ivojo.co.uk then this will take you to our new interactive-av.co.uk site).

Enter the information you have and click "Calculate". A list of matching projectors will be displayed.

In the tools section of our site you'll find the "Screen Wizard". (Note that if you are browsing www.ivojo.co.uk then this will take you to our new interactive-av.co.uk site).

Enter the information you have a click "Find". A list of matching screens will be displayed.

You have a couple of options here:

Select the projector you are interested in and click the throw chart thumbnail. A page will appear listing throw distances and a drop down list of the screens that Ivojo supply. Select the screen that matches your requirements and throw distance and foot lamberts figures will be returned.

In the tools section of our site you'll find the "Throw Calculator" tool. (Note that if you are browsing www.ivojo.co.uk then this will take you to our new interactive-av.co.uk site).

Enter the information you have and click "Calculate". A list of matching screens will be displayed.