LG 42LB5800 LED TV Review
The battle of the 2014 TVs is in full swing, but this LG isn't in it to win it.
Behind the Screens
The LG 42LB5800 (MSRP $699.99) didn't earn a top recommendation, and the Science Page illustrates why. On top of its mediocre black level, this TV also struggles a bit with accurate color production and grayscale errors. And, like so many LED LCDs before it, this one also has a pretty poor viewing angle.
Although Reviewed.com tests and rates TVs prior to calibration, we still like to make improvements to each TV and share the results here for interested readers. This way, we can see how a TV performs right out of its box, and what it's capable of with some informed menu adjustments. Note that our calibration shoots for dark, home-theater ideals.
Since the LG 42LB5800 offers controls for 2- and 20-point white balance and full CMS, our ISF-certified calibrator Lee Neikirk had plenty to work with. The main changes included lowering the TV's Backlight setting from 80 to 50, altering its gamma pre-set from 2.2 to 2.4, and executing fine-tune adjustments to the TV's white balance controls.
When a TV can plunge deep into shadow tones and ramp up powerfully in brightness, its picture looks very compelling as a result. That's because jet-black gloom and dazzling lightness creates a sense of true depth—a lifelike picture.
To investigate this aspect of a TV's performance, we divide its average 100 IRE brightness by its average 0 IRE brightness—or its bright and dark points. The resulting number defines a TV's contrast ratio. This LG was far from acing the test, with a piddling black level of 0.16 cd/m2 and a brightness of 195 cd/m2. That makes for a contrast ratio of 1189:1, which is around the baseline of acceptable performance in this category.
With LED LCD TVs, it's often the case that even slight off-angle viewing results in a big drop in contrast. Since light must travel from the backlight through severals substrates before reaching your eyes, light tends to scatter on its way there—and that means lowered contrast.
The LG 42LB5800 tested rather as expected, though a bit better than some of its competition. By measuring its contrast from head-on, and again at 10º intervals moving away from its center, I totaled this display's viewing angle: 52º. That means if you sit at more than ±26º from the TV's center, you'll experience a drop in contrast of more than 50%.
Measuring a TV's color gamut tells us everything we need to know about its spectrum. Using the Rec. 709 HDTV color standard, we can grade a TV's production for accuracy.
This LG's production suffered visible issues, but nothing make-or-break. Calibration helped, too. Nevertheless, its specific issues are as follows: Blue is ever-so-slightly the wrong hue, green is just a tad undersaturated, and red is mostly correct. The most-visible problem plagues cyan, though. Cyan colors appear too pale, and skew towards the green point. Yellow errs on the green side, while magenta wanders toward blue. Luckily, calibration straightened out most of the nonsense, and even corrected the white point.
Gamma is a performance point that tells us the manner in which a TV ramps up from totally black (0 IRE) to peak bright (100 IRE). For a home-theater, an ideal gamma sum is 2.4, meaning a TV ramps very gradually out of darkness, retaining great shadow detail along the way.
In its out-of-the-box cinema mode, the LG LB5800 is calibrated more for a bright room. We measured a sum of 2.04 which is far too bright for a dark viewing environment. Informed calibration brought the LG much closer to the dark-room ideal, however, delivering a final gamma sum of 2.38.
Grayscale & RGB Balance
A display's black, gray, and white tones make up its grayscale spectrum. Sometimes we find grays polluted by orange tones, or highlights that look very blue. That's largely because a television's grayscale production is an additive method that combines red, green, and blue sub-pixels to produce grayscale values. If the three sub-pixels aren't properly balanced, it results in unwanted color within the scale (measured as DeltaE).
Before calibration, the LB5800 tested with an unacceptable DeltaE of 9.96—a number I managed to lower to 4.47 (much closer to the ideal DeltaE of 3 or less).
One look at the initial RGB balance illustrates the grayscale issue. Out of the box, the TV emphasizes its green sub-pixel too much, creating a signal imbalance. Luckily the TV's 2- and 20-point white balance controls helped reign in the problems here.
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