Vizio VF550M 55-inch LCD TV Review
HDTVs with a diagonal screen size between 50 and 54 inches, such as this model, are LCDs, plasmas, or DLPs, usually with a resolution of either 1366 by 768 or 1920 by 1080 (1080p). The optimum viewing distance for HDTV screens like these is generally considered to be about 8 to 9 feet, making this model appropriate for large rooms such as a spacious den or living room, an entertainment room, or a great room.
Resolution Matches Blu-Ray Disc and HD Formats
All modern HDTVs are fixed-pixel displays. The number of pixels a display has determines its maximum resolution and thus the fineness of detail it can reproduce. Resolution is normally expressed as pixel width versus pixel height. This television’s resolution is 1920 by 1080, meaning it has 1920 pixel columns by 1080 pixel rows. Popular for midrange and high-end HDTVs of all types, especially those with large screens, this resolution matches the 1080i maximum resolution for broadcast HDTV and 1080p Blu-ray Disc formats. A key characteristic of all fixed-pixel displays is that incoming signals not at the set’s native resolution must be scaled to match that resolution. The quality of this mathematical upconversion or downconversion can significantly affect the picture, especially for ordinary standard-definition TV signals. Inferior scaling may soften the picture, exaggerate noise, or cause some edges to appear slightly jagged.
LCD Display Technology
LCD televisions, like this one, are relatively thin, lightweight panels with a light source at the rear and a lattice of tiny cells filled with liquid crystals in the middle. They perform better than plasmas in brightly lit rooms and don’t suffer image burn-in. But because the liquid crystal is never completely opaque, reproducing black or near-black color is harder for LCDs. Picture quality can deteriorate when viewing from far off to the side; and because liquid crystals respond relatively slowly to changes in applied voltage, fast-moving objects on the screen may appear to blur slightly. But LCD technology continues to improve, and these problems are less of an issue today (look for models that tout a 120-Hz refresh rate and a wide viewing angle). LCDs tend to be cheaper than comparable-size plasmas and are available in smaller screen sizes (37 inches and below).
Don’t Buy Based on Contrast Ratio
Contrast ratio is the ratio of a display’s light output at maximum brightness to its output at minimum brightness, or peak white to pitch black. The most significant limiting factor is usually the black level rather than the white, because true black is hard to achieve and white intensity can’t be taken too high without becoming uncomfortable. Unfortunately, published specifications are unreliable: Manufacturers use at least four “standard” ways to measure contrast ratio, each of which yields different numbers; and the numbers produced by any one method varies depending on the test conditions and display settings. Manufacturers don’t describe their methodology or test conditions in their specs, so don’t even think about comparing the contrast ratio of displays from competing manufacturers. Comparisons within a particular brand’s line may have some validity, but even then, be careful of reading too much into them.