LG PK750 review: LG PK750

People have been tolling plasma's death knell for what seems like years, but the "other" flat-panel technology is still available from LG, Samsung, and Panasonic. The first 2010 model we've tested is LG's PK750 series, and it exhibits the same plasma characteristics--better off-angle viewing and uniformity than LCD; worse energy efficiency--as ever. Its depth of black, though better than last year's LG plasmas, still can't compete with its brethren from those other brands' plasmas, or with the better LCDs available. That said, we appreciate the PK750's style and feature set at this price level, especially compared with similarly equipped 2010 models like the Panasonic TC-P50G25 and the Samsung PN50C6500. If you're looking for a midrange plasma and don't demand videophile image quality, the PK750 deserves consideration.

Series information: We performed a hands-on evaluation of the 50-inch model, but this review also applies to the other, 60-inch size in the series. Both sizes have identical specs and according to the manufacturer should provide very similar picture quality.

Design

LG uses its new-for-2010 minibrand "Infinia" to denote higher-end models, and like the LH8500 LCD, the PK750 shares a single-plane design and transparent edges for a sleek, modern look. Panel depth is a skinny (for plasma) 2 inches, out-slimming Panasonic's 2010 offerings by about an inch and a half, but coming up 0.5 inch deeper than Samsung, if you're counting. All-told LG continues to make the nicest-looking plasmas on the block in our opinion.

LG's new clicker is a long, thin wand with decent button differentiation and friendly, rubberized keys. We liked the bulge in the middle that corresponds with a convenient notch on the underside for your index finger; we missed direct infrared control of other devices. The menus are basic and functional with plenty of ways to get around, including a nice Quick Menu of shortcuts. We would have liked to see explanations, however, especially for the more-advanced picture setting functions.

Features

The PK750 is well-equipped for a plasma in this price range, hitting most of the basics. One omission is proper handling of 1080p/24 signals (see below), despite the fact that LG told us this panel uses a 96Hz refresh rate with such signals. The company's step-up PK950 series offers a "TrueBlack filter" and a higher contrast ratio spec, which might indicate superior black-level performance. We do know for sure, however, that the 950 has a fancy Wii-style remote not found on the 750.

Other notables on the PK750 include the external "LG Wireless Media Box" option that enables you to connect HDMI and other gear wirelessly, which can really help custom installations. We'd like to see built-in Wi-Fi, given all of the LG's Internet options, but you'll have to either buy the dongle or get a third-party wireless bridge. We tested LG's dongle, which worked well, but we didn't test the media box by press time.

LG's 2009 models were among the first to include Netflix, but since that service is now available on most Internet TVs, the company's Netcast array of streaming partners is now standard-issue. There are no major missing links, however, aside from any kind of audio service like Pandora or Slacker radio.

In our tests, Vudu and Netflix performed as advertised, delivering the video quality we expect from both services via both Ethernet and Wi-Fi from LG's dongle. We didn't test DLNA or USB streaming.

Most of the nonstreaming apps, with the exception of Picasa, come courtesy of Yahoo widgets. At the time of this writing the PK750 has access to 11 widgets. That platform is somewhat more usable than last year on LG, with snappier responses to button presses and faster load times for individual widgets. That said, it could be a lot faster still, and the initial load of the main widget taskbar can take 20 seconds or more--still an eternity on a television. In comparison, the apps platforms of Samsung and Vizio felt much snappier than LG's widgets, and content selection was wider on Samsung, Vizio, and Sony.

LG's games platform, not to be confused with the games included with Yahoo widgets, includes extremely basic custom titles, for example Sudoku and Whack a Mole--the less said the better about these pointless exercises in frustrating gameplay. Of course you'll need to buy the external speakerphone kit to use Skype. It hasn't been released (or priced) yet, so we didn't test it for this review.

In this area LG is among the best on the market for sheer numbers of adjustable parameters, but in the PK750's case the results were disappointing (see Performance). The TV's two Expert modes allow fine adjustment of 20 points of white balance, which seems like overkill compared with the 10-point system on the LH8500. The 750's 20-point system lacks the guidelines for gamma found on the 8500, but the 750 does offer LG's usual suite of other adjustments, including a standard 2-point system.

Plenty of presets are provided for those who'd rather not futz with settings. The two THX modes, one for bright and one for dim environments, are not user-adjustable, and there's a new Auto Power Saver Mode, again nonadjustable, that depends on room lighting to do its job. LG's Picture Wizard is on-hand to guide novices through basic settings.

In addition to the Auto Power Saver picture mode, you can apply one of three Energy Saving settings (each limits maximum light output) or an ambient light sensor to any non-THX picture mode. You can also choose a "screen off" option in the TV's energy saver menu to just get sound, reducing consumption to about 24 watts. LG calls its onscreen manual "simple" and that's definitely the case--it's more like a rundown of features than a usable manual.

Like most plasmas the PK750 offers three ways to combat burn-in, including white and color washes and a pixel orbiter, which shifts the whole image around on the screen. Since temporary image retention seems more common on this set than with other plasmas, we welcome the washes in particular.

There's nothing special here aside from the proprietary, optional wireless connection (see Key Features above), and no major missing links unless you're partial to S-video. The second USB port is nice if you monopolize the first with the optional wi-fi dongle.

Performance
LG's 50PK750 represents an improvement in picture quality over the company's LG 50PS80 model from last year, but it's still not up to the performance of the best plasmas and LCDs on the market. Black-level performance was a culprit, as was the display's inability to properly handle film-based 1080p/24 content. The PK750's color accuracy was a strength, although not as strong as some other LG models we've tested.

According to our measurements, THX Cinema was the best among the TV's presets for a dark room, so we used it for the Before numbers in the Geek Box below. It still suffered from relatively inaccurate gamma, averaging 2.61 overall (our reference is 2.2) as well as some loss of shadow detail. In the plus column, THX's grayscale was quite linear, except for dark areas, and light output was 37ftl, approaching our target 40 quite closely. You can't make any meaningful adjustments to picture quality in THX mode, however, so we decided to use the LG's Expert mode to address some of those issues.

Normally we use LG's IRE system for our standard calibration, but not in this case. After adjusting that system, which proved much more difficult than it has in the past, we saw significant false contouring artifacts (click here for a full explanation). Finally, as we did on the PS80 last year, we resorted to the 2-point system, which gave middling grayscale linearity but better gamma (2.31 overall) and shadow detail than THX.

After too much time spent tweaking, we finally spun up the Blu-ray disc of "Avatar," and moved on to the rest of our image quality tests using the comparison lineup below.

Black level: LG's PK750 delivered the second-lightest shade of black in our lineup, besting only the company's PS80 model from last year. The Samsung B650 was close but a bit darker, whereas the other displays in our lineup were all visibly darker than either. The difference was most obvious in black areas, such as the void of space behind the ship and the planets in Chapter 1, or the shadows inside Jake's brother's coffin. Compared with the darker displays, the PK750 looked less-realistic in these scenes on account of its lighter blacks, but not nearly to the same extent as we saw on the PS80. The PK750 still trails other plasmas (and some LCDs) in this area, but it's an improvement over past LG plasmas.

Shadow detail was as solid as the lighter black levels allowed; the folds in the black jacket of the RDA rep, for example, were visible yet slightly less distinct than we saw on the other sets (aside from the PS80).

Color accuracy: Although not equal to the best TVs we've tested in this area, the PK750 acquitted itself well in brighter scenes. Skin tones, like the face of Dr. Augustine as she confronts Administrator Selfridge, looked nearly the equal of our reference, whereas the lush primary and secondary colors in the film, from the green of the jungle to the orange-red of the rescue rafts in the dropship, were mostly accurate. One exception, however, was cyan, which is extremely common in the film; the light blue/green of the cryogenic barracks in Chapter 1, for example, appeared too intense compared with our reference. Of course saturation suffered somewhat compared with those models with better black levels, but it was still solid.

Dark scenes revealed the LG's tendency to veer into blue in the shadows, which was evident in the face of Jake as he speaks into his computer log in Chapter 15. This issue wasn't as obvious as we saw on some LCDs, such as the C8000, however.

Video processing: As with a couple of 2010 models we've tested, and with LG's 50PS80 from last year, the PK750 didn't handle 1080p/24 sources properly. In our test using "I Am Legend," for example, we saw the tell-tale hitching motion during the helicopter flyover of the deck of the Intrepid, whereas sets that handled the 1080p/24 source properly showed the smooth cadence of the film. We also noticed the difference during numerous pans in Avatar, such as the look at the underside of the Banshee rookery in Chapter 16. Adjusting the LG's film mode setting (available in non-THX modes only) didn't seem to help.

According to our motion resolution test, the LG delivered between 700 and 800 lines, which doesn't match the best plasmas or 240Hz LCDs we've tested, although it is better than typical 120Hz LCDs. As usual, we don't expect many viewers to notice, or even be able to see, the difference.

Update May 6, 2010 After this review published, a reader (thanks Shaddix Boggs!) alerted us to a strange video-processing issue we missed the first time. Some softness and ringing artifacts are visible in finely detailed areas. Those artifacts were too subtle for us to see in most normal program material, but we did see them in test patterns. Boggs also told us a method to remove the artifacts: we had to rename the input "PC" and watch a 1080p/60 source (1080i or 1080p/24 still showed the artifacts). Note that in that setting, some aspects of this review, including the picture settings we recommend above, may not apply, since we didn't test the TV extensively in that setting. We have no plans to do so, in part because many HD sources, such as cable and satellite, are not typically available in 1080p/60. We'll update this section again if LG issues a fix.

Uniformity: We normally skip this section with plasma TVs, since they most always have perfect screen uniformity and off-angle viewing characteristics. The PK750 did as well, with the exception of its higher incidence of temporary image retention, aka burn-in, compared with other plasmas we've tested. When we left an image paused on the screen for 30 seconds or more, we could often observe trace signs of it immediately afterward, especially in flat fields. On the other hand the traces disappeared quickly in every case, even extended, paused test patterns, so we don't consider this a big deal.

Bright lighting: Under the lights the PK750 was a relatively poor performer. Its screen reflected in-room lighting and bright objects more strongly than any of the others aside from the LH8500 and the PS80, and it didn't preserve black levels well either, washing out to a larger extent than any of the others (although again it equaled the PS80).

Standard-definition: The LG performed well with standard-def sources. It delivered every line of the DVD format and details appeared relatively sharp. Jaggies were minimal. Noise reduction performed well to clean up lower-quality source