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Projector Guide

Choosing a resolution

Digital projectors are available in a range of resolutions (click here for our glossary definition). Choosing the best one for the job at hand is critical to the look of your presentation.

The advice we give here is base on the native resolution of the projector (glossary). Most projectors have the facility to scale other resolutions to their own native resolution but this does sacrifice some image quality so should be avoided if possible.

If budget is a constraint and your presentations are made up largely of bold charts, graphics and text then an SVGA projector (800*600) should suffice but you should note that the number of SVGA projectors on the market is dwindling as prices drop and technology improves. If you want to have an element of future proofing the choose a resolution of XGA or higher.

The most popular resolution for business presentations is currently XGA (1024*768). This gives the best compromise between price and image quality and will be suitable for anything other than specialist presentations where details reproduction might be critical (medical, CAD, fine art etc.) There are a growing number of Wide XGA (WXGA, 1280*768) projectors coming onto the market which can be ideal if you have designed your presentation for wide aspect ratio displays.

To check the resolution of your computer use one of the following techniques depending on your operating system:

  • Windows XP - Right click on the desktop and select "Properties". In the window that appears choose the "Settings" tab. Towards the bottom of the window your resolution is under "Screen resolution".
  • 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 will show your resolution towards the bottom left.
  • Windows 7 - Minimize your running applications so the Windows desktop is displayed. Click the right mouse button and select "Screen Resolution". The window that appears will show your resolution towards the centre.
  • 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

Brightness

The second critical component of your projector is how bright it needs to be in order to display and image. The two main factors involved are image size and ambient light. Front projection technology throws an image onto a surface and it is the reflected image from this surface that you actually see. This means that the darkest you image can be as governed by the amount of light reflected from the surface whether it's from the projector, sun light or room lights. The ideal situation is to have no ambient light at all (room light off, blinds closed) but often this is not practical. Your audience may need to take notes or move about. In real terms this means that we would recommend at least 2000 ANSI Lumens (Glossary) for portable screen up to around 2 metres wide but remember that the brighter the projector the more flexible it will be in high ambient light situations. For larger screen you should try to use a brighter projector as the light from the projector is spread over a greater area. Please call us on 0844 332 0530 or email us if you require assistance or are looking at more specialist applications.

Portability

If you take the average portable computer as being about 2.5-3kg then the definition of portable as far as projector manufacturers are concerned is a bit subjective (anything up to about 8kg). Add the case, cables and accessories and you'll soon find a "portable" projector becomes an exercise in stamina over any distance. Projectors weighing less than 3kg are now available with output up to 3500 ANSI Lumens. Click here for a list of micro projectors.

Connectivity

Most of our projectors ship with a selection of leads which will enable you to connect a large variety of equipment. If you are running you presentation from a PC or laptop then simply connect the monitor output to the monitor input on the projector. With some laptops you may need to enable the external monitor port, see the laptop documentation to find out how.

If you're projector ships with a "mouse emulation" remote then you will also need to connect a usb cable (usually supplied with the projector) between the computer and projector.

Screens

The advantage, above all else, of modern projectors is the high light output. This means that in practical terms, virtually any surface will do, even a white wall can give good results in the right lighting conditions. That said, a decent screen can make all the difference to your presentation and make your image look that much more professional. So how do you choose? First and foremost is audience size. A small screen is better for small audiences as there is a limit to how much the eye can see at once and a smaller image will be brighter as there is less light dispersion, you don't want a large screen making your presentation less personal because people need to sit a long way back to take in the whole image. Be wary of high gain screens, the general rule is, the higher the gain, the narrower the viewing angle so if your audience is somewhat spread out, use a normal gain screen.

Unfortunately, the ideal screen size is a subjective decision and there's no set formula for the ideal screen to audience size ratio.

If you're on the move, make sure your screen is easily portable.There's no point in a ten foot screen if it won't fit in your car and you don't want to look foolish fumbling about with a screen you need a winch to erect.

Lens zoom

Most projectors come with a zoom lens which allows a little more leeway in how far a projector is placed from a screen to project a given image size. This can be very useful for the presenter on the move, so is worth considering. These zoom features are, however, limited to quite a small range. The reason for this is the added complication in the mechanics of the projector and the reduction in performance. The mechanical side is simply the fact that the projection lens has to move in order to zoom in and out. Because the lens needs to be very accurately aligned, the more movement allowed, the more the risk of lateral movement which causes focus problems and distortion. Also, the ideal shape of a lens changes as focal length changes (which is why zoom lenses are not considered to be as good as fixed focal length in camera circles) and so there is always a compromise with zoom lenses. Lastly all lenses have a single point in front of them at which they are in focus. The area in front of and behind that point which is so close to being perfectly focused that it looks focused is called the depth of field (you can see the effect by looking at a photo of someone which is focused on the person but everything behind them is out of focus). This depth of field decreases as the focal length increases, which makes focusing harder. You needn't worry about this as these built in limits in projectors mean that you'd never notice any picture degradation anyway.The performance is just a case of the further the lens is from the light source (the projectors lamp) the less light gets through. So, the longer the distance, the dimmer the image. Again, because of the limited zoom, there's no perceptible loss of brightness.

Insurance for field presenters

Make sure your office/company insurance covers you while transporting, setting up and using equipment outside the office, bearing in mind that many insurance policies have clauses requiring you to inform the insurer of any equipment you own or use over a certain value.

Summary

So the specs. to look for:
  • Resolution - Try to match the computer resolution and design you presentations with this in mind.
  • Brightness - How large is you audience and what are the lighting conditions.
  • Portability - Are you going to be travelling with the projector? If so, choose a light one.
In accordance with normal business practice you should inspect the equipment on receipt and be sure of its condition before signing for it.

©Ken Davies, Ivojo Multimedia Ltd.