This quick guide has been created to help you choose the projector that will meet your requirements.

Projectors are usually compared using these main factors:

• Brightness

•Resolution

•Aspect ratio

Once these factors have been considered, you can narrow down your choice further with secondary factors such as contrast ratio, warranty, lamp life etc.

Projector Brightness:

Brightness is measured in ANSI (American National Standards Institute) lumens: the higher the ANSI lumens level, the brighter the projector.

 So how bright should your projector be? First you need to consider the following factors:

Can you control the light in the room?

The best results, regardless of projector brightness, are obtained in a dark room; however it is not always possible to control the light.

If you are going to use the projector in a room where there will be lighting or where there aren't any curtains to block out the natural light, it is recommended to choose a projector above 2000 lumen.

The more light there is in a room the brighter the projector will need to be in order to compete.

What is your application?

Projecting text, graphs or any other detailed material from PC will require a brighter projector because of the need to see and read the details of what is being projected. These applications will also require some amount of ambient light for note-taking and communication.

The more detailed the image/picture, the brighter the projector.

Once you have decided the factors of room brightness, image size and what you will be projecting, you can decide what level of brightness is best for your application.

Less than 1000 Lumens:

Most projectors in this category are for home cinema applications as they are used in dark rooms to ensure an optimal picture quality (contrast levels).

 Business projectors in this category are to be used in darkened rooms so that the image isn't washed out by ambient light.

1000 to 2000 Lumens:

The majority of projectors in this category are for education use, in classrooms or training rooms. Projectors between 1000 and 1500 lumens may need reduced lighting for better results; projectors between 1500 and 2000 lumens do not require a totally dark or dimly lit room to give a good picture.

2000 to 3000 Lumens:

These projectors are suitable for large conference rooms, classrooms and portable use.

Most projectors sold to business and education users belong to this brightness range.

They will be able to cope with increased levels of ambient and natural lighting and a larger screen.

More than 3000 Lumens:

Projectors brighter than 3000 lumens are typically used in large venues such as auditoriums, churches, concerts etc. where a large screen is required or in very bright environments.

Projector Resolution:

The resolution is the number of pixels that make up an image - e.g. 800 x 600 means the picture is made of 800 columns of pixels by 600 rows of pixels; for a total of 480.000 (800x600) pixels making up the whole image. The larger the number of pixels the higher the resolution and the sharper and more detailed the image is.

When comparing projectors, we are comparing their native resolution: most projectors are compatible with higher source resolution through the use of compression technology, but the native resolution is the actual number of physical pixels.

SVGA         800x600

WVGA       854x480

XGA           1024x768

WXGA       1280x800

SXGA+       1400x1050

UXGA        1600x1200

HD             1920x1080

What resolution is best for you?

Projectors are compatible with different resolutions, converting different input resolution to the native output resolution. This process is called 'scaling'.

However, scaling always causes a loss of picture quality: it is not as sharp and detailed. This happens not only when the projector is of lower resolution than the source but also when the projector is of higher resolution.

Therefore it is always advised to match the projector resolution to the source's resolution (e.g. if you are using an XGA laptop you should if possible use an XGA projector). This will ensure you are getting the sharpest and cleanest image.

Another factor in choosing the right resolution for your projector is the typical application:

If you are using the projector for 'Powerpoint' type applications, you don't need a very high resolution; SVGA should be enough.

If you are using the projector for numeric data presentations, 'Excel' spreadsheets etc. where the image needs to be clearer, XGA is recommended.

If you are projecting highly detailed technical data such as engineering drawings, or high end photography, SXGA or UXGA resolutions would be best.

If you are using a widescreen computer or are buying a projector for home cinema, choose a widescreen projector that will match the computer resolution or the quality of video you would like to have.

Projector Aspect Ratio:

The aspect ratio is the ratio of the width of an image to its height.

Projectors are divided between 4:3 (computer monitor shape) and 16:9 (widescreen TV shape) aspect ratios.

The 4:3 projectors are mainly used for business purposes to use with a computer.

The 16:9 projectors are used for home cinema or to project DVDs.

There is also a 16:10 aspect ratio seen in widescreen business projectors. These projectors have been designed for use with widescreen computers, although they are also used by home users.

Most projectors, whether they are 4:3, 16:10 or 16:9, are compatible with other aspect ratios. A simple option in the projector menu will switch the picture between formats. It is however not recommended to use a projector in a format other than its native aspect ratio as it will stretch the image or it will miss parts of the picture.

The ideal aspect ratio depends on the application:

If you are going to use the projector mainly for business presentations, training, classroom application etc. with a standard computer it is advised to choose a 4:3 projector.

If you are using the projector with a widescreen computer it is recommended to choose a 16:10 projector.

If you are using the projector for home cinema or to project DVDs to an audience, it is recommended to choose a 16:9 projector.

Once you have answered these questions (brightness, resolution and aspect ratio), you should be able to shortlist a few projectors.

To determine which one is best, you can also consider the following factors:

Contrast Ratio:

This is the ratio between white and black. The larger the contrast ratio the greater the ability of a projector to show subtle colour details and tolerate extraneous room light.

Inputs and Outputs:

If you are planning on using multiple computer or video inputs it is recommended to choose a dual input projector. This will save you switching input every time you want to change the source which can be difficult if your projector is installed out of the way or can be inconvenient during a presentation.

Lamp Life and Price:

Depending on the use of the projector, the lamp will have to be replaced from every few months to every few years. Most lamps last on average 2000hrs but some claim to last up to 5000hrs. Prices vary but some lamps cost around €300. It is therefore important to take into consideration the price and life of the projector lamp.