The benefit of a local-dimming, full-array LED backlighting system is that it can turn off the LEDs around portions of the screen to create true blacks, while still allowing bright areas to remain bright. If there's a night sky at the top of the screen, for instance, those LED backlights can be turned off, while the LED backlights at the bottom of the screen can remain on ... and remain bright. The resulting image has excellent contrast, with a greater sense of depth and richer colors. In comparing the two TVs, black portions of the image were comparable, but the 55LH90 appeared to have even better overall contrast, creating a wonderfully rich, dimensional image.
I set the backlight at about 20 to 30 percent, which proved a good fit for dark or bright conditions in my viewing environment; however, the panel can be very bright if you turn up the backlight. I don't recommend a zero backlight setting, as it makes the panel too dim and flattens out the image. The 55LH90 uses a matte screen, so light reflectivity isn't an issue, but I will say that the Samsung Ultra Clear Panel (which is reflective but designed to reject ambient light) rendered a slightly deeper-looking black during the day.
With HDTV and 1080p Blu-ray content, the 55LH90 also did a slightly better job rendering fine details. On a larger 55-inch screen, the picture doesn't have that razor-sharp look you often see on a smaller LCD, but it's not lacking in the detail department.
One of the drawbacks to LED technology in early-generation models is that, because the number of LEDs used in the backlight is not a 1:1 ratio with the number of pixels, the lighting effect is imprecise. For instance, if you look at white text on a black background, the text appears to glow, something that doesn't happen with a plasma TV, in which each pixel generates its own light. In a demo scene from Lost: The Complete Second Season on DVD (Buena Vista Home Entertainment), in which two people sit in front of a campfire at night, the LG produced some unintended glow around lighted areas, and the transitions from light to dark occasionally tripped up the local-dimming function, as it struggled to figure out which LEDs should be on and which ones should be off. Compared with the first-generation Samsung LED, though, this LG model was more precise, with less glow around edges, so the technology is clearly making progress.
In terms of color, the LG and Samsung displays are similar. Both TVs have an out-of-the-box color temperature that veers too cool, even in the Warm color-temperature mode. With the LG, this is true even in the THX picture mode; and, since you can't make any picture adjustments in this mode, you can't dial in a more neutral color temperature. Whites and blacks veer blue, and skin tones look a bit flat, with a hint of red. On the positive side, the LG's color points are very close to those of the Samsung, which is accurate in this respect. The 55LH90's red and cyan needed some tweaking, which again you can't do in the THX mode. In the Expert modes, however, I had all the controls I needed to fine-tune the individual color points and dial in a more neutral color temperature, which made colors and skin tones all the more inviting.
In its handling of 480i DVD and SDTV content, the 55LH90 did a much better job than the Samsung, particularly through the HDMI inputs. As long as the Real Cinema mode was turned on, the LG passed all of my deinterlacing tests with 480i content, both with test discs and real-world demos from Gladiator (DreamWorks Home Entertainment) and The Bourne Identity (Universal Studios Home Video). It's a bit more difficult to make standard-def content look highly detailed on a large 55-inch screen, and the LG's performance is only average in this regard. You won't mistake 480i sources for HD, but there was a solid level of detail in both DVD and SDTV content.
I was also impressed with the 55LH90's handling of some of my favorite DVD tests for black detail, noise and bit depth. While black detail was somewhat lacking in the THX mode, the adjusted Expert mode did a good job with fine black details in The Bourne Supremacy (Universal Studios Home Video) and Ladder 49 (Buena Vista Home Entertainment). The TV rendered a clean image, with minimal noise in the smoke-filled backgrounds of Ladder 49. Facial contours and light-to-dark transitions were smooth with both standard- and high-def content.
The common LCD problem of motion blur is easier to detect on a
larger 55-inch screen like this one. That's where TruMotion comes in
handy. With the detail tests on the FPD Software Group BD, the 55LH90
produced a cleaner picture with TruMotion enabled; one of my favorite
tests shows a camera panning slowly and then quickly over a world map.
With TruMotion off, you could not read much of the text. With TruMotion
on, it was easy to read all of the city names. During an HD football
telecast, finer details in the background were better preserved with
TruMotion enabled. If you're especially sensitive to motion blur, I
highly recommend you use TruMotion with sporting events.
Competition and Comparison
If you are looking for an LED HDTV be sure to check out the LG 55lH90's competition by reading our reviews for the Sharp LC-46LE820UN LED LCD HDTV and the Vizio M550NV RazorLED LCD HDTV. Another good source of information is our All Things LCD HDTV section.
The TruMotion technology is successful at reducing motion blur, but its success in eliminating film judder is debatable. I'm personally not a fan of motion interpolation, and LG's implementation is no exception, although I will admit that the low TruMotion setting is more subtle in its smoothing effects than I've seen with other displays. Still, even when using a 24p source, the low mode occasionally hiccupped and introduced some stutter or smearing, which I find more distracting than judder. Even when I enabled the Real Cinema mode, which the manual says engages 5:5 pulldown (in which each frame is simply repeated five times), it looked artificially smooth, as if motion interpolation was still occurring. So I opted to turn off TruMotion with film sources. If you go this route, however, you lose the blur-reduction benefits. It's a tradeoff I'm willing to make, as I'm less bothered by blur than by interpolation. This issue could be solved by splitting up the blur reduction and de-judder features, the way Samsung does with its newer LED-based displays. Even if you like the effects of motion interpolation, TruMotion doesn't perform reliably with TV signals (most de-judder modes don't), often introducing smearing and stutter into the picture. It's best to use the function only with DVD and Blu-ray movies. With that in mind, I'd like to see a TruMotion button on the remote that makes it easy to turn the function on and off on a source-by-source basis.
It's disappointing that the 55LH90's THX mode isn't more accurate. Black detail could be slightly improved, and the color temperature and color points could be dialed in more closely to accurate standards. Plus, because you can't make any image adjustments in the THX mode, you can't use the THX image as a foundation and go from there to improve the picture. This said, the THX mode is still the best-looking and most accurate of all the 55LH90's preset picture modes, so it's the plug-and-play choice for someone who doesn't want to mess with the picture set-up yet still wants a nice-looking image.
As with most LCDs, the 55LH90's viewing angle is only average. Bright scenes retain decent saturation at wider angles, but darker scenes look washed out, and black detail is lost.
Finally, while the 55LH90's video processor does a nice job of de-interlacing 480i content, it surprisingly falls short with 1080i film-based sources. The TV failed the film resolution loss test on the HD HQV Benchmark BD, and it produced blatant moiré in the stairs at the opening of chapter eight of the Mission: Impossible III BD (Paramount Home Entertainment), with my Pioneer BD player set for 1080i output. This isn't a concern when you're mating the TV with a good Blu-ray player that outputs all discs at 1080p through HDMI, but it is a concern with HDTV content, as a number of channels transmit the signal at 1080i, including CBS, NBC, TNT, and others. I noticed more jaggies and other digital artifacts than I usually do on these stations. Frankly, I'm surprised that a THX-certified display would fail this processing test.
This proved to be an interesting review. Two of the 55LH90's big-ticket features - the THX mode and TruMotion 240Hz - didn't exactly wow me. I recommend calibration over the THX mode, and I would only use TruMotion with sports or video game content. Yet the success of the 55LH90's marquee feature - LED backlighting with local dimming - overshadows the other issues. Take some time to set up this TV properly, and you'll be rewarded with a great-looking picture. Furthermore, the 55LH90 is loaded with picture adjustments and connections, and the cabinet design is easy on the eyes to boot. At $3,000, the 55LH90's price is on par with Samsung's LN55A950 (which is no longer available through Samsung) and much less expensive than Sony's KDL-55XBR8. If you're in the market for a big-screen flat panel and desire a higher level of performance than a traditional CCFL LCD can provide, LG's 55LH90 is definitely worth a closer look.
• Read a review of a sister product, the LG 47LH40 LCD HDTV.
• Read many more reviews of LED HDTVs from HomeTheaterReview.com.
• Learn where to buy the LG 55LH90 LED HDTV.