One of the biggest differences between the old CRT-style TVs of yore and the new LCD, plasma and DLP HDTVs is the actual shape of the screen. While older TVs were nearly square — four parts by three parts, known as 4:3 — newer TVs are a very distinct rectangle, 16 parts by 9 parts (16:9). With this new aspect ratio comes some confusion about exactly which mode is right to display each source of video. Keep reading, as we answer the basic questions behind aspect ratios and aspect ratio modes.
There are a few standard aspect ratios used in video and film. We've already mentioned 16:9 and 4:3, but there are a few other aspect ratios that crop up frequently. 3:2 is a common aspect ratio for photography, while 1.85:1 and 2.39:1 are both common with hollywood movies. Whatever the numerical equivalent, all of the five common aspect ratios have specific purposes and all can be displayed by your HDTV.
HDTVs have a few ways of displaying differing aspect ratios. Each mode will either stretch, zoom or crop the image differently, and each mode can be used with differing results.
One of the methods used frequently on 4:3 video by consumers is the full or stretch mode. Like the name implies, the video from the source is simply stretched to fill the frame. In the case of 4:3 video, that stretching makes objects take on a wider look than they'd normally have. Stretching video is appropriate for TV watchers who'd rather fill the frame with video than maintain image quality. As you can see in our above image, the circular logo is stretched wide into an oval.
If the sidebars are still getting on your nerves, but you don't feel like ruining the whole image, Panorama mode is a middle of the road approach. Panorama stretches the outer edges of the picture progressively, filling the sidebars. The progressive stretching makes the center maintain its aspect ratio, but as is clear with the picture above, text and other objects in the wider parts of the frame are stretched. Quick pans left to right can also produce an extremely uncomfortable view, since the video is quickly being stretched and unstretched as the video pans from left to right. Panorama is best for "regular" TV programs that don't utilize very much movement, or ignore the outer elements of the frame. Local news is a perfect candidate for Panorama, while fast motion videos like sports are better off with another mode.
The last mode is for shoehorning other widescreen aspect ratios into a 16:9 frame. HDTVs typically offer two or three Zoom / Crop modes. The first crops 4:3 video into a 16:9 frame by zooming the video in, and then chopping off the top and bottom of the video. The other modes aim to eliminate letterboxing of content that is from cinematic sources. Most films are nearly 16:9, but most are just a tad shorter than regular 16:9 video in the case of 1.85:1, or much shorter than regular 16:9 in the case of 2.39:1. Other Crop / Zoom modes will zoom in the picture to eliminate the black bars at the top and bottom normally associated with watching movies on a TV.
When viewing a 4:3 source on a 16:9 TV, most TVs give an option as to which color sidebars the watcher prefers. At first, it might seem like a good idea to go with a simple black sidebar, but with plasma TVs especially, black sidebars can leave faint ghosting after the source changes. To avoid the ghosting, TV manufacturers provide gray sidebars. Gray isn't as high contrast as black, which means the ghosting effect won't occur. Modern plasma TVs are nearly immune to burn-in, though ghosting is still fairly common. The choice of sidebars is really an aesthetic one to minimize annoying ghosting effects. My TV is set to dark gray, for the record.
Now you're up to date on exactly what each aspect ratio setting does and how it affects your picture. Have any other questions you need answered? Hit our tips form and let us know, or leave a comment on the post and we'll fill you in.
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