Plasma Televisions: Converting a 4:3 Image to Full Widescreen

Reviewer: Phil Connor

Plasma televisions have a widescreen 16:9 aspect ratio, which states the dimensional relationship between the screen's width and height. This is the proper aspect ratio for HDTV viewing, and is also the best aspect for DVD replay. What happens when viewing a regular TV or computer image? Does the image look stretched? There are several aspect ratios which plasma displays use to size the incoming video image. All plasma screens can show the image in its original 4:3 format with bars (either black or gray) on the sides of the image. There can be some variation among plasma screens in how well they convert a 4:3 image to the widescreen monitor. Manufacturing engineers accomplish a best of all worlds approach by limiting the stretching in the center of the screen and also by enlarging the entire image size to larger than the screen size. This scaling technique allows the most stretching to be located on the sides of the image thus reducing visible distortion.

So the answer to the question is that a viewer may watch the image on the plasma screen in a variety of ways when displaying an incoming "normal" or 4:3 picture image from satellite, VCR, or cable TV. It can be displayed as is with the bars on the sides. In Zoom mode the image will have very little distortion or stretching and will fill the entire screen area. However, this mode usually is not favorable because it cuts off too much of the picture image and also because it causes motion artifacts and pixelation, or grainy appearance. The 16:9 aspect option will not be the preferred method of converting a 4:3 image because it will be the most visibly stretched and distorted of all the options.

The best option for converting a 4:3 NTSC TV signal to the widescreen monitor is the "just" or "full" mode. Each manufacturer calls this mode something different. This aspect ratio option converts the 4:3 image with specially designed algorithms, which reduce the visible "stretching" as much as possible by using a combination of techniques. The end result is that the viewer will get passable performance and be able to enjoy the full screen dimension of the plasma display. This is accomplished by slightly enlarging the picture past the actual viewing area of the plasma panel while keeping the center of the picture more accurate. The sides of the image will appear slightly more distorted and stretched but the overall result is acceptable for long and short-term viewing. Much will depend upon what the viewer is watching. When I watch sports such as football or golf, I prefer to watch the original 4:3 format to see the most accurate production possible. When watching movies or sitcoms or the news, I watch the converted full screen mode. Of course, HDTV is shown in widescreen, which gives the widescreen format an advantage on future viewing.

When using the sidebars for extended periods of time there can be a ghosting effect when then viewing an image filling the entire screen. To cut down on the ghosting or help to eliminate it, switch back and forth from 4:3 and full screen viewing. If side bar ghosting is apparent you can reduce or eliminate the effect by displaying a gray signal on the plasma display for a few hours. A VCR or DVD can be used to get the gray static image. As well, just by using the full screen size for an extended period of time can bring the plasma screen to normalcy again.