Sony KDL-40W5100 LCD HDTV Review - Blacks & Whites |
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Published on August 25, 2009 Comment on this |
Black Level (6.29) Deep blacks are a much sought-after quality. A deep black gives the potential for more detail in dark scenes. A TV without a low black level has a sort of "bright" darkness that most find visually unappealing. The KDL-40W5100 wasn't capable of a particularly impressive black level. When displaying an all-black screen, the TV still output about 0.22 candelas per square meter (cd/m2). To put this in context, 0.1cd/m2 is typically the threshold of a "good" black level: below 0.1 cd/m2 is great, above is not so great. Although the KDL-40W5100 falls squarely into the category of "not so great," it wasn't that bad compared to other LCDs. As you can see in the chart below, some LCDs can get up to 0.4 cd/m2 or higher. Don't expect some crazy plasma-esque black level from the KDL-40W5100, but expect it to be decent for an LCD.
One of the KDL-40W5100's "features" is dynamic backlighting, which can't be turned off. Dynamic backlighting is bad because it causes a loss in detail for the brighter parts of a dark scene. In the KDL-40W5100's case, the feature seems to have some intelligence behind it: if the center of the screen is bright, the screen won't dim. We noted that the backlight only dimmed when the middle 80% of the screen (or more) was dark.
Peak Brightness (9.38) The screen was capable of a healthy peak brightness. We measured an all-white screen at 407.82 cd/m2. This is much brighter than average. The bonuses of a bright screen include better detailing in bright scenes and less interference from outside light. With a low peak brightness, a nearby light source might wash out the content on the screen. The only thing that'll cause much of an issue with the KDL-40W5100 is if it's by a window and catches the sun.
Contrast (7.07) Contrast refers to the ratio of the brightest white to the darkest black. Contrast is an important aspect of picture quality, because our eyes are very sensitive to it. A viewer would have more difficulty seeing fine details on a screen with a poor contrast ratio than they would on a screen with a higher ratio. The KDL-40W5100 had a weak black level and a high peak brightness. We measured the contrast ratio at about 1853:1, which is average for an LCD. This means you might lose some minor details, but the lost clarity won't be anything that would bug the average viewer.
Tunnel Contrast (8.77) Our tunnel contrast test checks to make sure the TV's black levels maintain consistency, regardless of how much of the screen is actually black. Although the KDL-40W5100 has dynamic backlighting, it's unlikely to affect normal viewing too adversely. The only issue that might crop up is that the dynamic backlight could be a bit jarring. Once the TV recognizes it's displaying a dark scene, the backlight dims slowly and evenly. After a set time, however, there's an abrupt two-stage dim with no transition between the start, middle step, or end result.
White Falloff (9.80) This test is an inverse of the above test. Here, we're checking consistency in white levels. Ideally, a fully white screen should have the same brightness as a tiny block of white on an otherwise black screen. Typically plasmas do poorly on this test: they can display small blocks of white, but the block will dim as it gets larger. This "white falloff" happens because otherwise the TV would run too hot. The KDL-40W5100 performed well on this test, like most LCDs. We thought it was interesting that the dynamic backlighting didn't come into play here, even when only 5% of the screen's center was white. Again, it seems the dynamic backlighting feature looks at where the brightness is occurring; if the bright area is close to the center of the screen, the dynamic backlighting won't activate.
Uniformity (7.88) Screen uniformity can often affect picture quality, but has nothing to do with the TV's actual performance. A non-uniform screen might have blotchy patches, darkened edges, or overly-bright corners. While the KDL-40W5100 had a uniform screen overall, it did have some issues. When the screen was black, we noticed a darker circle on the left side of the screen. The left-most half of this circle was haloed by a brighter patch. This effect didn't seem to affect picture quality much, however. The only other issues we saw were dimming around the edges and flashlighting in the corners.
Greyscale Gamma (5.42) Greyscale gamma refers to the curve along which grays darken to black or brighten to white. We measured the Sony KDL-40S5100's gamma at 2.96, which is much higher than the ideal of 2.2. A gamma that's close to three leads to washed out details in certain areas. The TV does have a gamma control, and we were able to get the gamma down to a more acceptible level using it. Unfortunately, altering the gamma in this way had adverse effects on the color temperature and RGB response. If you don't mind taking a hit to color accuracy, boost the Gamma up to +3 to boost detailing.
Resolution Scaling (8.41) Just because a TV says "1080p" on the side doesn't mean it's always displaying 1080p content. In fact, unless you're exclusively watching Blu-ray discs, it probably spends more of its time displaying other formats. Standard definition broadcast TV runs at 480p, DVDs play at 720p, and broadcast HD content is 1080i. In order to play these other formats, it has to do a lot of internal processing to upscale these lower-resolution formats to fit on its 1080p display. 480p (8.18) 720p (7.80) 1080i (9.25)
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• Deep black level, bright peak white, and high contrast ratio. 
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