[…] is 1080p, but the difference is not really noticeable from normal viewing distances. Have a look at what makes for a good HDTV here, and good luck with your […]
When shopping for an HDTV, what should you look for? One thing to keep in mind is that the average big-box showroom is no place to compare TVs. Why? The TVs are always in torch mode – with contrast and brightness maxed out, on an incorrect picture quality mode and usually under bright fluorescent lights.
All the factors that separate the TVs in quality are lost under such circumstances! Try to find an environment where you can apply the correct settings (usually a movie mode or similar comes closest to the HDTV color standard) and compare the following aspects of picture quality, in order of importance.
The most important aspect to video quality, above everything else, including resolution (1080p vs. 720p) is contrast ratio. Our eyes see things in almost infinite contrast, at least when compared to viewing images on displays. In order for a video image to appear lifelike, the contrast should be as close as possible to our own vision. Imagine a scene of a black car driving down a road on a bright, sunny day. In real life, the sun would be so bright that we couldn’t look at it. When looking at the car, you’d be able to distinguish between the black paint of the car, and its black tires. If you were to look at this image on an HDTV with a poor contrast ratio, the difference between the blacks and the bright sun would not be enough to create a believable image. On a top-end, high-contrast display, the same image would have a lot more contrast and “pop,” to the point where one might experience the “looking out the window” sensation.
The problem with contrast ratios reported by manufacturers is that they are basically useless as a tool for comparison. They are drastically overestimated and sketchy techniques are used to estimate wildly inaccurate ratios, such as 50,000:1 for an LCD HDTV. Realistically, LCD HDTVs have typically ranged from 500:1 to 1300:1, until recently, where the best-performing LCDs have achieved 3700:1 (The Samsung A650/750/850 LCDs). Similarly, with plasma displays as well, inaccurate ratios are provided by the manufacturer, with 10,000:1 being the highest contrast ratio available on an HDTV today (all Pioneer plasmas).
How can manufacturers get away with this? There is no industry standard testing method, and no governing body. Manufacturers will also “cheat” by using certain types of patterns and using dynamic irises (they control brightness and contrast on the fly) to achieve results that are impossible to duplicate in the real world.
Black levels go hand in hand with contrast, in fact, contrast ratio is a measurement of the whitest white divided by the blackest black.
Peak brightness, however, is not really an important measurement. Don’t be fooled by bright displays. That is not what to look for in an HDTV. In an ideal setting, you want the brightness on your TV to be a certain amount; most professionals calibrate HDTVs to output light at no more than 35-40 foot-Lamberts in a pitch-black setting. Any more, and there would be serious eyestrain, not to mention an unrealistic image.
Why do black levels matter so much? When black levels are poor, they wash out the picture. Dark areas, such as shadows aren’t as dark as they should be, so the image loses realism, and it appears that one is viewing the image through a filter or screen. If the TV in question has a poor black level, it can’t display anything below that level, so details will be lost, and dark colors will get very inaccurate. Apart from that, you don’t want to glowing bars on the top and bottom edge when watching 2.35:1 movies, or bars on the left and right side when viewing 4:3 content, right?
Everyone understands that color accuracy is important for a good picture, but perhaps not how important it is. It is more important than resolution! Good color accuracy, along with contrast ratio and black level, will make the image appear significantly more realistic, and therefore more believable. Some HDTVs are more accurate than others, but pretty much all sets need to be heavily adjusted from the settings at the store. HD video has a color standard, and it is not difficult to have your TV calibrated so that it is extremely close to perfect color.
Color saturation is also very important to good image quality. In the showroom, saturation is often turned up very high, along with brightness, which is very misleading. The image should appear natural, so it should have just the right amount of color to it. Any more, or any less will make the image appear unrealistic.
If contrast, black level and color accuracy are equal, higher resolution video will look sharper. Under ideal conditions, 1080p video can look fantastic, and better than 720p video, which itself is a big jump over 480i/p video. At this time, the only 1080p sources are Blu-Ray disc, some video games on the PS3 (even though the XBOX 360 can output at 1080p, no games at this point are natively 1080p), and a computer input at 1920×1080.
Higher resolution is especially noticeable in static scenes, as with motion, resolution is lost. Some TVs lose more than others, for example, the Samsung L52A650 and Pioneer PDP-5020FD show more than 1000 lines of resolution, even with motion, whereas the Sony KDL-52XBR6 shows between 400 and 600 lines of resolution when there is motion.
Awesome explination! Easy to understand info that seems to have been driven into the coffers and shadows of an increasingly idiodic public, fooled by the rediculous propoganda of super bright LED and LCD manufacturs. Is it possible to bring plasma back from the brink and educate the public back into buying a “quality” product? This article certainly can’t hurt!