Buyer's Guide to Business Projectors: Resolution

The amount of data that can be displayed on the screen at any given time is determined by a projector's resolution. Resolution is simply the number of pixels the projector uses to create the image. The more pixels it uses, the higher the resolution.

Resolution is usually quoted in two numbers, such as "1,024 x 768," where the first number refers to the number of pixels from side to side across the screen, and the second number refers to the number of pixels vertically from top to bottom.

Resolution can be quoted in other ways, as well. For example, 1,024 x 768 is also known as XGA, for eXtended Graphics Array. This terminology is primarily used for computer monitors, but extends to projectors as well. Since there is little rhyme or reason to this naming scheme, the only way to learn it is memorization. Common resolutions will be discussed later in this article.

When speaking of a projector's resolution, it is common to refer to "native" resolution. If a projector's native resolution is 1,024 x 768, that means that the actual number of physical pixels on the display is 1,024 pixels per horizontal row by 768 pixels per vertical column.

How much resolution do I need?

High resolution projectors are able to show more picture details than low resolution projectors. Since there are more pixels used to make the image, each individual pixel is smaller, so the pixels themselves become less visible on the screen. However, you will pay more for higher resolution.

Lower resolution projectors are much less expensive, and they can produce images that are just as bright and attractive as higher resolution machines. Unless you have a need to display fine detail, lower resolution products will be your best bet from a cost perspective.

Resolution options

Some basic choices for native resolution are the following:

1. SVGA, or 800 x 600 - SVGA projectors are great for those on a tight budget, since prices have dropped dramatically in recent years. While most computers still output in higher resolution, SVGA can be a good option for powerpoint presentation or other applications that are not heavily dependent on detail.
2. XGA, or 1,024 x 768 - XGA projectors have come down in price over the past few years, and have become the budget standard. Most computers still output in native XGA, so matching an XGA projector to your computer ensures you won't lose any detail.
3. SXGA, or 1,280 x 1,024 - SXGA products are high resolution, and notably more expensive than XGA. These products are targeted for high end personal computer users and low end workstation users. They are used primarily for command and control, engineering and CAD/CAM applications where acute resolution of small details is important.
4. SXGA+, or 1,400 x 1,050 - SXGA+ projectors are becoming more popular, and there are several offerings available in both budget and high-end configurations. SXGA+ resolution is useful for detailed photography and data graphics, but overkill for text display or Powerpoint presentations.
5. UXGA, or 1,600 x 1,200 - UXGA is for very high resolution workstation applications that are detail or information intensive. These are expensive projectors that support a broad range of computer equipment. Relatively few products on the market have this native resolution.

Which resolution is right for you?

One of the key factors in choosing the right resolution is your typical application. Do you have a need for very accurate display of small visual details, or are you looking for a general presentation tool for text and small graphics?

If your primary use of the system is for Powerpoint presentations, pie charts, graphs, Excel spreadsheets, and general business display, you probably don't need to pay extra for very high resolution equipment. SVGA or XGA resolution projectors are perfect for this kind of work, and the best solution for the money.

If you are projecting engineering drawings, digital photography, or other images of a highly detailed or technical nature, you will probably need a projector of SXGA resolution or higher to produce an acceptable image for your purposes.

Matching your computer to your projector

Keep in mind that the best resolution for your projector is the resolution of the computer you intend to use with it. If you typically use a notebook computer with XGA resolution, you will want a projector with the same native XGA resolution in order to get the sharpest and cleanest image. Similarly, if you normally use a computer with higher than XGA output, such as SXGA+, you will get the best picture from a projector that has the same native resolution.

Projectors on the market today are capable of projecting input signals other than their native resolutions. For example, you can usually hook up an XGA computer to an older SVGA projector. The projector will automatically convert the incoming 1,024 x 768 signal to its native 800 x 600 output. However, there is always a loss of sharpness and detail in the process, so you will end up with a picture that is not as sharp or clear as if the incoming signal had been in the projector's native resolution.

This loss of sharpness also happens if you plug an XGA computer into a higher-resolution SXGA projector. You will usually get a decent image, but the conversion from 1,024 x 768 input to a 1,280 x 1,024 output will produce some softness that you may not appreciate after having spent the money for an SXGA projector. The loss in quality incurred by making a small resolution larger is generally less severe than that incurred by making a large resolution smaller.

The projector's process of converting a different input format to its native output format is called scaling. Making a small resolution large is known as upconversion, while making a large image small is known as compression. Some projectors are very good at scaling, so the resulting image softness is relatively minor, and quality degradation is almost negligible. The quality of scaling varies widely among projectors and like all technology, it is constantly being improved. Scaling is an important consideration, so whenever possible, try to see the projector demonstrated as you would use it.