The Do's and Don'ts of Buying a Used Projection System

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The Do's and Don'ts of Buying a Used Projection System

For home cinemas, there are few better options than using a projection system to obtain large and striking pictures. Projectors can also be used for other purposes; for example, giving presentations or viewing slide shows.

Choosing a Used Projection System

Which projection system is chosen depends upon its primary usage and picture quality as well as factors such as budget and portability. These often need to be weighed up against each other. Outlined below are the various do's and don'ts to consider when buying a used system.

Do Remember that Technology Advances Quickly

Buying a used projection system is a cheaper option to buying a new system. However, the technology used in projection systems has advanced rapidly over the years, which is something to be aware of when purchasing a used system. It may be better to pay a little more for a slightly newer system than an older system which may have noticeable issues, such as the screendoor effect or rainbow effect, both of which are discussed below.

Do Visit Review Websites and Forums

Manufacturers' websites may not have details for older systems, even relatively recently manufactured projectors, but review websites and forums may be able to give information about a particular model's picture quality, features, and any issues.

Don't Dismiss Problems

If particular problems keep cropping up with particular models, it is probably worth looking around some more, even if the projector seems like a great bargain. Likewise, if a manufacturer or seller has received negative reviews for their customer service or response to fixing problems, it may be better for peace of mind to shop elsewhere.

Do Check for Damage and Missing Components

Always take the same precautions when buying a used projection system, as with any other electronic purchase. Check all the necessary parts are included and that the product is free from serious defects. If offered for sale in working condition, it should be perfectly functional. It may, however, have some cosmetic damage or non-essential parts missing. Photographs may illustrate this, and many sellers will include them in any product description. Cases are handy if the projector is to be moved on a regular basis, and the manual is also useful to have.

Do Compare the Different Types of Projection System

The two most common types of projector are liquid crystal display (LCD) and digital light processing (DLP). LCD projectors are well known for their excellent colour saturation and comparatively better resolution, but their drawbacks include pixilation, reduced contrast and washed out blacks. Visible pixilation leads to an effect known as the screendoor effect. This makes the picture appear as though it is being viewed through a mesh screendoor, with numerous tiny squares overlaid on the image. Reduced contrast and washed out blacks affect picture clarity.

All these problems are lessened in newer LCD projectors. DLP projectors tend to display better contrast and deeper blacks than LCD projectors, but they also tend to have paler colours and less contrast. Also, the colours can appear separated out in the image, a visual artefact known as the rainbow effect. The rainbow effect is largely viewer specific; in other words, not all viewers notice it, and the level at which it becomes noticeable to different people (if ever) varies. Newer DLP projectors with improved designs are less susceptible to it, or not at all. Other display technologies are gradually increasing in popularity and use, and these includeLED, LCoS and laser projectors.

Do Check the Resolution and Aspect Ratio

Projectors with a higher resolution will be able to display sharper, clearer pictures. Standard resolutions are measured in pixel number and are also named. The total pixel number is obtained by multiplying the number of columns by the number of rows. While lower resolution projectors may be sufficient for some purposes, the use of higher resolution projectors will make a significant difference in many cases.

For example, when it comes to watching high definition (HD) films or displaying fine detail on presentations, higher resolution projectors are recommended. Pictures can be enlarged to a greater extent with higher resolution without losing clarity. Resolution is connected to aspect ratio, the width to height ratio of the picture, as aspect ratio is determined by the number of pixels. Most projectors have either a 4:3 or 16:9 aspect ratio. 4:3 is the aspect ratio of a standard computer monitor and is best for presentations, lectures, meetings, and similar situations. The table below shows the resolution of some standard 4:3 projectors.


800 x 600 pixels

480,000 total pixels


1024 x 768 pixels

786,432 total pixels


1400 x 1050 pixels

1,470,000 total pixels


1600 x 1200 pixels

1,920,000 total pixels

16:9 is the ratio of a widescreen television, and for home cinema use, this ratio is generally recommended. The table below shows the resolution of some standard 16:9 projectors. 720p and 1080p are commonly used resolutions, with 1080p recommended for better high definition (HD) viewing.


854 x 480 pixels

409,920 total pixels


1280 x 720 pixels

921,600 total pixels


1920 x 1080 pixels

2,073,600 total pixels


2048 x 1080 pixels

2,211,840 total pixels


4096 x 2160 pixels

8,847,360 total pixels

Some projectors have a 16:10 ratio, which corresponds to that of some widescreen computer monitors. 16:10 projectors can also be used for home cinema use without much issue. The aspect ratio can actually be changed on the projector, but this can distort the picture. The tables below show the resolution and aspect ratios of 4:3 and 16:9 projectors.

Don't Be Too Concerned with Lumens

Projector brightness is usually measured in American National Standards Institute (ANSI) lumens. This is considered the most accurate standard. How bright a projector is required to be depends upon factors such as ambient light, audience, and purpose. For home cinema use, it is assumed that the audience ranges between one person and a small group, and the room is not larger than a large living room. Room size is an issue because larger rooms require larger pictures so that people further away can see them. This in turn requires the projector to transmit a brighter picture. With regards to ambient light, better results are seen in a dark room.

If the room is lighter, the projector will also need to be able to transmit a brighter picture to compete. For home cinema use, however, the room will usually be darkened, so the projector does not need to be as bright to obtain the same contrast levels. Lastly, the brightness of a projector indicates its capability to project fine detail. This is not usually so much of a consideration with home cinema as, for example, with business presentations making use of small spreadsheets and detailed graphs. Home cinema projectors vary in brightness. Up to around 2000 lumens is fine for a normal sized picture in average size darkened or slightly lightened room. Anything more will provide clearer pictures over a larger sized screen or in a lighter room.

Find a Used Projection System on eBay

There are several used projection systems for sale on eBay. To find one, simply start on the eBay homepage and open the Electronics & Technology tab, selecting the Sound & Vision option. From the tabs to the left, selectDVD, Blu-ray & Home Cinema and then Home Cinema Projectors. The tabs now display various options to select the most appropriate type of projection system; for example, with regards to resolution and aspect ratio. To find a used system, scroll down, and under the heading Condition, select Used. Another way to find used projection systems on eBay is to search using the search bar at the top of the page. Try typing in terms such as "used projection system" or "used LCD projection system" to bring up results.


Buying a projection system used rather than new is a great way to save money, but always check out a particular model before committing to purchase. This can be done by visiting review websites and forums as well as by studying the specification. Remember that older systems are in general more prone to problems such as the screendoor effect and rainbow effect, found on older LCD and DLP projectors respectively. Other important considerations are the resolution and aspect ratio.

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