LG 50PK790

The LG 50PK790 is a plasma TV.  Even though this technology isn't the best choice for PC monitors or games consoles because of screen burn, it's a great alternative to LCD on televisions because it often represents great value for money with excellent results.

Build Quality and Design

These days, a TV is a designer object that people want to show off in their front room.  The last plasma we tested, the Panasonic G20 didn't exactly knock us off our feet, but fortunately, LG has taken a little bit more care over what its TV looks like, slicing almost half the thickness off: it's just 5.3 cm from front to back despite a diagonal size of 50''.

You'll find all the inputs and outputs you need around the sides and at the back, including four HDMI ports, two USB ports, an Ethernet port, an optical audio output, VGA, composite and component video and SCART.  That makes the PK790 compatible with DLNA networks for playing your multimedia content. 

We took a slightly closer look at the PK790's media player, which, unlike most of its competitors, can access files stored on devices formatted as NTFS and FAT32, which opens up the possibility of accessing files that are larger than 2 GB.  Most AVC (x264) HD videos worked fine, as did content encapsulated in MKV files.  On the other hand, M2TS and MTS didn't play.  If you like enjoying your movies in the original language, then subtitles are Well-handled as long as they're not part of the same file as the video.  If you put them in the container, you'll not get them out again on the TV.

Even the remote hasn't been overlooked and it too has a new design.  It still doesn't have backlighting to make it easy to use in the dark.

The onscreen menus look modern, with animated icons showing you the way and making navigation quick and easy.  The only downside is that the interface is sometimes a little slow, but it generally works quite well.



Image Quality: Factory Settings

With its factory settings, the PK790 is in 'Standard' mode, which produces a really eye-catching picture designed to wow newcomers.  Unsurprisingly, that gives a very unnatural look, with light shades very close to being burnt out and very inaccurate colours produced by a strong blue tinge.


Image Quality: THX and ISP Expert Modes

Fortunately, you can move over to either 'THX' or 'ISP Expert' (the latter offering control over more technical settings) which solves most of these problems.  Our equipment measured a deltaE of 3.4 which is a distinct improvement and a good result in its own right, even though a lot of TVs can do better.  A screen's deltaE score is the difference between the colours provided on the test card and those actually produced on screen.  When this value is below 3.0, then any remaining effects are generally considered to be invisible to the naked eye.

As with most plasma TVs, we struggled to get the brightness above 170 cd/m² in white areas.  That's not too bad if there's only a little bit of ambient light around, but if you're in a very bright room, it might not be be enough—especially as the glossy panel also exacerbates the problem because it's so prone to reflections.

We measured black levels of 0.06 cd/m², which is a great score.  The PK790's contrast ratio is a very good 2800:1.

During our tests, this TV proved to be particularly susceptible to screen burn, so we can't recommend using it with a PC.  However, it's possible that if we let it really warm up first then this problem would improve over time.

Of course, the upside to plasma technology is the excellent viewing angles.  That said, you need to be at least three metres away, otherwise you can see the individual plasma cells flickering. 

As with most TVs, upscaling SD sources on the PK790 isn't quite right.  We suggest you leave the job to an external device like a DVD or Blu-ray player or your PS3.

Finally, we were disappointed not to see any system for improving the smoothness of rapidly-moving objects.  When this feature is implemented properly, it can cut out the jerkiness introduced by the 24 frames per second used in films.  Apart from this one missing feature, the overall picture quality is good and plenty of viewers will be happy with it.

Sound Quality

While our eyes were having a great time with the great picture quality, our ears had less fun with the built-in speakers.  The sound they produce lacks a lot of bass, and the fact that they point down away from the viewer doesn't help much either.  That's why we suggest using some Home Cinema speakers so the sound quality is as good as it is what's on screen.

Energy Consumption

This last point is the TV's real weak spot: energy consumption is absolutely minimal while it's on standby—just 0.1 W-but is much higher when the TV is switched on.  Our equipment revealed an energy consumption of 385 W for the 50'' version on the PK790, which is two to three times as much as an equivalently-sized LCD.