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LG Infinia 50PK790 50in Plasma TV Review

Key Specifications

  • Review Price: £1029.41

LG has been threatening to make a great plasma TV for quite a few generations now. And the 50in 50PK790 is in most ways the closest the brand has ever come to achieving this greatness. Yet frustratingly, it still doesn’t quite get there, due to one really strange flaw.

We could tell you about this flaw right away, of course. But this would be a bit unfair. For the TV also gets a lot of things right, and so once you know about all the good stuff, it’s possible the flaw I’m talking about might not put you off at least considering buying a 50PK790. Especially as the flaw might not actually be permanent.

Right, this is all getting far too mysterious and cryptic. So let’s get down to the more straightforward reviewing business.

The 50PK790 gets off to a great start by doing what the Korean brands seem to do better than anyone else: looking great. For starters, it sticks out a mere 53mm or so round the back – startlingly slim for a 50in plasma TV. Plus it boasts a sleek finish, bold lines, and the single-layer fascia (where the bezel and screen exist in the same plane) that’s now become a trademark of LG’s ‘posher’ televisions.

One little concern I’d have about this design is the way the top sheet sticks out beyond the main bezel edges, making the TV a little uncomfortable to hold and easily breakable during installation. But of course, these issues only apply when you first get the TV home. Once it’s up and running, you won’t have to worry about them again.

Given how slim and thus wall-friendly the 50PK790 is, it might have been nice if LG had positioned all of its connections with a sideways orientation, a la Samsung’s UE50C8000, rather than having them sticking straight out of the TV’s rear. But at least the connections provided are impressively plentiful.

Four HDMIs get the ball rolling in fairly predictable fashion, but it’s the various multimedia options that really catch my eye. There’s an Ethernet port, for instance, which can do triple duty as 1) the means to use future interactive services delivered by Freeview HD (for yes, it’s another LG TV with a built-in Freeview HD tuner); 2) a means to access files on a DLNA PC; and 3) a connection to LG’s burgeoning new online NetCast service.

I might as well say here that NetCast is currently a limited affair, with just the Picasa online photo album site, YouTube and AccuWeather sites available at the time of writing. But hopefully services such as Skype and maybe a few more video streaming sources will be added to the platform – via free downloaded updates – soon.

The 50PK790 has a USB port to its name, too, through which you can play JPEG photos, MP3 music files and even DivX HD video. Or else use it to make the TV ‘wireless’ via an optional USB Wi-Fi dongle.

The 50PK790’s most innovative connection, though, is one you can’t actually see: Bluetooth. This lets the TV wirelessly stream in photos and music from Bluetooth enabled phones, or send audio wirelessly to a pair of Bluetooth headphones.

LG has done a great job in recent years of providing its TVs with exceptionally comprehensive set up tools, which here results in endorsements – and picture presets – from both the THX group and the Imaging Science Foundation.

The sort of tools available to these professional – and you amateur! – calibrators include an extensive colour management system, as well as gamma adjustments, and all manner of switchable small-fry picture processors such as dynamic contrast and colour boosters.

While this all has the potential to make the 50PK790 quite complicated to use, in fact it’s a breeze, thanks to a superb GUI that’s easy to follow and careful to make sure you only need to delve into its options as deeply as you feel comfortable with. There’s even a little Picture Wizard feature that generates a few test patterns and guides you through how to use them to make your picture look better.

Aside from the 50PK790’s use of a 600Hz sub-field drive engine similar to that sported by Panasonic plasma TVs, the only other, slightly curious feature worth mentioning is a small collection of ultra-basic games tucked away on internal memory. Though to be honest, these games are so ultra-basic that it’s hard to imagine anyone older than three actually playing them for more than five seconds.

The 50PK790’s picture quality is for the most part a big improvement over the slightly disappointing efforts of many of its previous plasma generation.

Especially impressive is how much deeper blacks manage to get when the TV is showing dark scenes. There’s only the faintest trace left of the quite pronounced greyness I’d noted on last year’s models, leaving dark scenes looking natural, layered, detailed and dynamic.

It should be said that the 50PK790’s black levels don’t quite keep up with those of Panasonic’s recently reviewed TX-P42G20B, but that doesn’t stop them from rating as excellent by affordable flat TV standards.

I also found the 50PK790’s colours to be far superior to those of LG’s previous plasmas, since this time they combine LG’s trademark punchiness and vibrancy with much more accurate and subtly differentiated tones. These tones hold up markedly better than they did on last year’s models, too, when you switch to a standard definition feed – though there’s still room for improvement here.

Next, the 50PK790’s pictures are phenomenally sharp with HD sources, especially since the accuracy with which proceedings are mapped to the screen’s Full HD pixel count isn’t disturbed by any significant motion blur. There’s only the tiniest trace of judder, too – and what judder there is actually looks pretty natural to my eyes.

There seem to be less obvious processing side-effects to the set’s motion processing as well, making it an easier choice to leave the ‘Film Mode’ on more or less permanently.

And now to reveal that aggravating flaw mentioned right at the start of this review: image retention.

Basically, throughout the few days that I had the 50PK790, my use of it was constantly blighted by extremely distracting residual ‘echoes’ of bright, colourful image elements hanging around over subsequent images – sometimes for as much as an hour at a time.

And before you ask, no, I’m not talking about a phenomenon that only happens if I leave the ”Sky News” logo playing uninterrupted for a good few hours. Even bright image content that’s only been on screen for a few seconds can still be clearly, annoyingly visible on the next few frames, especially if those subsequent frames are predominantly dark.

The only time I ”did” experimentally leave the ”Sky News” logo running on the screen for any significant amount of time – a couple of hours, I guess – I could clearly see its ghostly outline hanging over anything else I watched afterwards for at least an hour, possibly more.

Of course, plasma TVs used to suffer quite routinely with image retention, and were renowned for falling prey to permanent screen burn if you really pushed your luck. I also know that plasma TVs are more prone to image retention during the first 100 hours or so of their life, so I’d expect – though can’t guarantee – that the problem will reduce as the 50PK790 gets older.

But even so, there’s simply no getting round the fact that the retention problems on the 50PK790 are troubling even by old plasma standards, and shouldn’t exist to anywhere near this extent on a 2010 plasma model. And before you ask, I was so concerned about the problem that I ordered a second model from LG’s new range, the step-up 50PK990, and found that this suffered with the same problem, albeit to a lesser extent.

This really is a hugely frustrating issue that for me – as someone who hates anything that distracts me from what I’m supposed to be engrossed in watching – spoils what might otherwise have been a potential ‘TrustedReviews Recommended’ TV. Sigh.

For the record, the audio the 50PK790 produces to accompany its nearly-great pictures is above average. There’s not as much bass as I’d like, but this is a common flat TV failing, and at least the 50PK790 does better than many rivals at presenting an open, detailed, distortion-free mid-range that seldom feels underpowered.


If you’re a patient sort willing to put up with the 50PK790’s image retention problem for a good many hours after you first get the TV, then presumably – hopefully?! – your patience will be rewarded with a really good all-round picture performance once the retention problem has gone.

But why should you have to be patient with LG’s plasma TVs when similarly accomplished TVs from other brands work fine straight out of the box?

Trusted Score

Score in detail

  • Features 9
  • Value 8
  • Image Quality 7
  • Design 9
  • Sound Quality 8


Size (Inch) 50in
Display Type Plasma
Max. Resolution 1920 x 1080
Digital Tuner ATSC
Contrast Ratio 3000000:1

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