LG PZ850 (50PZ850T) Full HD 3D Plasma TV Review

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Is LG's Pentouch technology a 'touch' too much?

by Steve Withers Oct 31, 2011 at 12:00 AM

  • TV review


    LG PZ850 (50PZ850T) Full HD 3D Plasma TV Review
    SRP: £999.00


    The 50PZ850T is LG's latest 3D plasma, sitting below the PZ950 in the hierarchy but incorporating active shutter 3D and their new Pentouch feature. Given that we were a little disappointed with the 50PZ950T, especially in terms of 3D performance, when we reviewed it earlier in the year, we are curious to see if things have improved. We are also curious about the Pentouch feature and whilst at first glance it appears to be something of a gimmick, we are prepared to keep an open mind. So let's take a look at the 50PZ850 and see how it performs under our rigorous testing regime.

    Styling and Connections

    If the design of the PZ850 seems familiar that's because it is and it would appear that LG have been influenced by their Korean neighbours. The silver brushed metal bezel bears more than a passing resemblance to Samsung's current crop of displays and the stand clearly shares some DNA with Samsung's quad foot design. The Razor Frame bezel itself is 3cm wide at the top and sides and 6cm wide at the bottom and there is a gloss black plastic trim around the outer edge of the bezel. Along the bottom on the right hand side there are touch sensitive controls for On/Off, Input, Home, OK, Volume and Programme. The chassis is 4cm deep with a metal back and entire display is quite heavy which gives it a solid and well engineered feel.

    The stand uses the quad style approach with four feet and consists of silver plastic over metal, it is attached to the rear of the chassis by two metal columns. The stand matches the design of the chassis and overall the look is quite attractive and a nice change from LG's usual gloss black approach. The panel doesn't have a TruBlack filter but instead has a protective screen cover that is designed to stop the screen from getting scratched by the touch pen but this cover is quite reflective. At the bottom centre of the rear of the chassis there is a power cable connected using a three-pin plug which makes a change from the hardwired cables we have seen on most plasmas this year. In fact, the 50PZ850 appears to be using a lot of technology from last year's panels which might explain the three-pin power cable and certainly explains the configuration of the connections at the rear.
    The connections, with their combination of rearward and sideways facing connections are very reminiscent of last year, right down to the number of HDMI inputs. At the rear there are only two HDMI inputs, a VGA connector, a LAN socket, two SCART sockets, an analogue audio in and component video in, both using RCA connectors, an optical digital out, an antenna connector and a RS232 connector. At the side there is an additional HDMI input as well as a USB 2.0 port, a composite video and an analogue audio input both using RCA connectors and a CI (Common Interface) slot. Despite there being three HDMI v1.4a sockets there doesn't seem to be one designated as an Audio Return Channel (ARC) and strangely there is no headphone socket. This is disappointing and is the same combination of connections that we saw on LG's entry level plasmas, which also use a lot of last year's technology - the difference of course is that the entry level plasmas are half the price of the 50PZ850.

    The 50PZ850 comes supplied with the standard LG remote control which is made of glossy black plastic but overall it has a pleasing ergonomic design, it is comfortable to hold, intuitive to use, has buttons that are sensibly laid out and a backlight. As well as all the standard buttons that you would expect to find, there is one called Home that provides access to the menu system and a dedicated 3D button. The remote control also has LG’s Q.Menu button that brings up a shortcut to either the key 2D or 3D menus.

    Whilst not strictly a remote control, the 50PZ850 also comes with a touch pen that can be used in conjunction with special software to allow you to write on the TV and interact with your PC. The touch pen comes with a cloth case and a holder that can be attached to the 50PZ850's chassis to keep the pen in. It can also be recharged using the USB socket on the 50PZ850 in much the same way as the 3D glasses can.

    The 50PZ850 includes a pair of LG's latest AGS250 active shutter glasses, which have a slightly retro look to them but we found them light and comfortable to wear. However we also found that they let far too much ambient light in at the sides, would have benefited from larger lenses and due to their snug fit they were also difficult to wear over normal glasses. On the plus side they can be recharged via the USB port on the side of the 50PZ850, they come with a cloth case and additional pairs can be bought for about £60.

    Menus and Set Up

    The feeling that the 50PZ850 utilises a lot of older technology is reinforced by the menu system that is more in the style of 2010 models rather this year's versions. First of all the 50PZ850 doesn't have Smart TV so when you hit the Home button on the remote you are taken to the standard menu screen from last year. This isn't necessarily a bad thing as we find having to constantly go through the Home page to get to the menu system on this year's displays quite a nuisance.

    Setting up the 50PZ850 initially was fairly straightforward, you just tuned in the Freeview HD channels, a process that took about 10 minutes which is much longer than we are used to these days. The resulting EPG is well laid out and easy to use with an attractive design that retains the audio as you navigate through the channel choices.

    As with last year's menu system, you access it by just pressing the Home button on the remote control, although you can also access the Picture and Audio menus using the Q.Menu button on the remote control. We found the responsiveness of the menu system to be quite slow and this could be quite frustrating when going in and out during the calibration process. Once in the main menu page there are ten sub-menus each represented by an appropriate icon: Setup, Picture, Audio, Time, Lock, Option, Network, Input, Pentouch and My Media.

    Within the Picture menu there is an option for choosing the Aspect Ratio as well as LG's excellent Picture Wizard and an Energy Saving function. The Picture Mode gives you a choice of different settings including Vivid, APS, Standard, Sport and Game but of more interest to the AV enthusiast are the pre-calibrated THX Day and THX Night settings and two ISF settings. These ISF settings, called Expert1 and Expert2, allow a professional calibrator to access advanced picture controls and then lock them once finished.
    Within Picture you will find all the standard controls such as Contrast, Brightness, Sharpness, Colour and Tint which can be accessed from all the presets, as well as a Picture Reset function.

    In ISF Expert1 or Expert2 there is the Expert Control sub-menu where you will find Dynamic Contrast which tries to boost the contrast ratio by changing the Brightness and Contrast controls on the fly, a Noise Reduction control, a Black Level and the Film Mode function which controls the deinterlacing of film based material. There is also the Colour Gamut control which offers a choice of Standard and Wide and the Edge Enhancer which acts like an additional sharpness control.

    The Expert Control also allows you to select the Colour Temperature where the choice is between Warm, Medium and Cool as well as control the Gamma with a choice of Low, Medium and High. The 50PW450 has both 2 point and 21 point White Balance controls, which should allow for very accurate calibration of the Greyscale and Colour Temperature.

    Finally, within Expert Control, there is a Colour Management System (CMS) which should allow for an accurately calibrated Colour Gamut. In the CMS there are controls for the three Primary Colours (Red, Green and Blue) and the three Secondary Colours (Cyan, Magenta and Yellow). The actual controls are Colour which sets the saturation and luminance and Tint which sets the hue.


    The major new feature on the 50PZ850 is the Pentouch function which allows the user to utilise touch pen supported features like Sketchbook, Photo Editor, Family Diary, Internet and My Office. To do this you need to install the Pentouch programme onto your PC and connect the PC to the 50PZ850. You then need to connect a USB dongle driver to your PC and pair it with the touch pen. You then configure the PC screen, activate the Pentouch mode on the TV and start the Pentouch programme. The software works with Windows XP, Windows Vista and Windows 7 but if you use an Apple then you're out of luck.

    Once set up you can then use the touch pen in conjunction with a number of functions including Sketchbook which allows you to select a background and then draw pictures on it. There is also Photo Editor which allows you to draw or edit pictures on photos and videos and Family Diary which includes a journal of photos, videos, notes and sketches for family events by date. You can also use Gallery in which you can store a collection of pictures drawn and saved in Sketchbook, Photo Editor, Internet and My Office. Finally you can launch a web browser to capture web content and then draw and write memos on it and the software also supports the glass effect in Microsoft Office and PDF files.

    Frankly we've seen some fairly useless features on TVs in recent years but Pentouch might just take the biscuit. Aside from possibly in a school environment, we really can't see any use for this feature and we found it complicated to set up and clunky to use. All of the features found on Pentouch can be done on a PC faster and better and frankly we found it a complete waste of time. In addition the inclusion of the Pentouch function means that the 50PZ850 itself has very limited internet and streaming capabilities of its own. We would prefer it if LG just concentrated on producing TVs that delivered excellent pictures, rather than wasting their energy on gimmicks like this.

    Test Results

    As is always the case before we began these measurements, we made sure that all the special features had been turned off and then optimised the Brightness, Contrast settings for our viewing environment. We could do this easily enough for the ISF mode but in THX mode all the controls are locked out so we couldn't adjust the Brightness and Contrast controls. This proved to be unfortunate as both THX modes were clearly crushing the blacks and shadow detail and there was nothing we could do about it. We have pointed out to LG that they should at least allow users to optimise the Brightness and Contrast settings in their THX modes, just as Panasonic do in their THX modes. As it is, users are forced to enter the service menu to adjust the THX settings, which is non something we recommend as it might invalidate the warranty and possibly cause unwanted problems.

    The first chart represents the performance of the ISF Expert1 mode and it's far more accurate than the THX mode. The DeltaEs are actually below 3 up to 60 IRE and Gamma Luminance is tracking better than the THX mode. There are still some errors from 70 to 100 IRE and Gamma itself has a spike at 90 IRE but it is smaller than in the THX mode and overall the performance is a little better. Since the 50PZ850 has a 21 point White Balance control, we would expect to improve this still further.

    Based on the CIE chart above the ISF mode has almost exactly the same colour gamut as the THX mode, with the same inherent problem of under saturated colours in red and blue. Whilst the 50PZ850 includes a Colour Management System (CMS) the luminance and colour controls are not separate which will make it difficult to adjust when one aspect is over saturated and the other is under saturated. In addition, even if the CMS did have full independent controls for hue, colour and luminance it still wouldn't be able to correct under saturated colours because you can't add what isn't there.

    As the above chart shows we were able to calibrate the greyscale to produce DeltaEs of less than two or better and now all three primary colours are tracking around our target of 100. The Gamma Luminance has a slight bump at 80 IRE which is reflected in a similar bump at around 80 and 0 IRE, however overall this is an excellent greyscale performance.

    As you can see from the CIE chart we have managed to improve the colour accuracy in some areas. The aspect of colour that our eyes are most sensitive to is luminance (or brightness), so we have ensured that these are as accurate as possible. We have also managed to improve the hue accuracy which has resulted in overall errors that are less than three for most colours except blue and magenta which are just over three. As we mentioned previously, a CMS can't add what isn't there, so the errors caused by the under saturated red and blue remain and these are also causing an error in magenta since it is a combination of red and blue. However, the overall colour performance isn't too bad and these errors were not really noticeable when watching actual material.

    Video Processing

    This year LG is at the head of the pack in terms of video processing with all of their 2011 models being able to pass our testing process and we would expect the same of the 50PZ850. As usual we started with our PAL and NTSC HQV benchmark discs and first of all we checked the SMPTE colour bar test which the 50PZ850 easily passed, correctly scaling the full 576i and 480i images without any loss of detail or unwanted ringing. The 50PZ850 also scored well when it came to video deinterlacing with jaggies only appearing when the line was at an acute angle in the first test. In the second test the motion adaptive deinterlacing was also good with slight jaggies only appearing on the bottom bar of the three moving bars.

    The 50PZ850 performed well in the film detail test and correctly locked on to the image resulting in no aliasing. In the cadence tests the 50PZ8500 also correctly detected both the 2:3 (NTSC - USA/Japan) format and the 2:2 (PAL - European) format. The 50PZ850 also correctly displayed film material with both horizontal and vertical scrolling video text, correctly displaying the words without any blurring or shredding.

    The 50PZ850 performed very well in all of the tests on the HQV and Spears & Munsil Blu-ray discs using high definition content. With the player set to 1080i the display correctly deinterlaced and displayed both the video and film resolution tests (provided the aspect ratio is set to Just Scan) and showed good scaling and filtering performance as well as good resolution enhancement. The 50PZ850 also had no problems in showing video text overlaid on film based material and also handled 24p content without any problems, even the tortuous wedge shaped test on the S&M disc.

    Using the S&M disc we checked the headroom performance of the 50PZ850 from reference white (video level 235) up to peak white (video level 255) and it was very good with absolutely no signs of clipping. In addition, the 50PZ850 also correctly showed detail down to a video level 17 and reference black below that to video level 0, as long as you had Black level set to High. If you used the Low setting the blacks will appear darker but you will be crushing them and you will lose shadow detail.

    Gaming Performance

    LG have really struggled with input lag this year and the 50PZ850 is no exception, with an input lag that measured around 80ms in Game mode, which for a plasma is very high. It might not be an issue for the casual gamer but will undoubtedly be too slow for the more dedicated player. LG have brought out a number of firmware updates to try and address the issue but the best we have managed from any LG display this year is 45ms, which is still too slow.

    Energy Consumption

    As has been the case with some of LG's other plasmas this year, we found the energy consumption to be quite high, even for a plasma. Due to the self-illuminating nature of plasma technology, the amount of energy being used depends on the content on screen. The brighter the image the greater the amount of energy needed and vice versa. We measured an average energy consumption of 220W in the calibrated mode, which increased to 300W in 3D mode, although in standby mode the 50PZ850 used less than 1W. This relatively poor energy efficiency is another reason why we suspect the 50PZ850 incorporates a lot of last year's technology.

    Picture Quality - 2D

    As is often the case, the combination of excellent scaling and deinterlacing coupled with an accurate greyscale and decent colour gamut resulted in a very pleasing standard definition image on the 50PZ850, with DVDs in particular appearing very clean and artefact free. The Freeview HD tuner also performed very well and, depending on the broadcaster, resulted in some very good images, especially with high definition material which retained a level of detail despite the display's lower native resolution.

    High definition images looked even better with the full 1080p resolution panel showing all the detail on Blu-rays and high definition broadcasts. The results were very pleasing with the accurate greyscale and colour gamut really bringing out the best in the content. The 50PZ850 was also able to handle motion very well, displaying 24p material smoothly, without introducing any judder.

    However, the 50PZ850 was surprisingly dim in both ISF and THX modes, measuring only around 92 cd/m2 which is low even for a plasma. The 50PZ850 could produce much brighter images in the THX 3D mode but the brightness seem restricted in the ISF and THX 2D modes. The lack of brightness resulted in a limited dynamic range that was made worse by some equally poor blacks. Whilst blacks have never been LG's strong point, the absence of a TruBlack filter on the 50PZ850 resulted in rather poor black levels, with a 0IRE screen measuring 0.08cd/m2. As a result of this compromised dynamic range the images lacked any real punch and often felt rather insipid.

    Despite the poor blacks, the level of shadow detail was at least reasonably good and although we didn't see any noise in black parts of the image there was green noise in areas that were 5% above black. However you could only see this noise up close and once you moved to a sensible viewing distance it became invisible. As is the case with all plasmas, there was also some Pulse Width Modulation (PWM) noise to the overall image when viewed up close, especially in the brighter parts, but from a sensible viewing distance this wasn't an issue. We also noticed some image retention on occasion, which is another reason to think that the 50PZ850 uses an older panel.

    Picture Quality - 3D

    Whilst we have been impressed by the quality of the 3D on LG's passive displays we have found the 3D on their active displays to be somewhat compromised. This was certainly the case with the 50PZ950 and was also the case with the 42PW450 and 50PW450 that we reviewed. However, thankfully things were much improved with the 50PZ850 and in fact the 3D was actually quite good.

    We feed the 50PZ850 a host of different 3D content from frame sequential 3D Blu-rays to side-by-side TV broadcasts and the display took them all in its stride. Images appeared solid and natural as they moved through positive to zero to negative parallax and there was very little crosstalk or other artefacts. The 50PZ850 seemed to have no problems handling the various depth cues and was capable of rendering some quite impressive 3D images.

    The larger screen size also helped making the experience more immersive and the glasses worked well without adding any flicker or losing sync. The 50PZ850 also handled motion very well and moving images had a smooth and natural feel to them. Because of their dimming effect, the glasses also helped with the black levels and the 3D THX mode appeared to offer a reasonably accurate and bright image. LG's active shutter might not be as good as some other manufacturers but it is good to see that have become more competitive in this area.


    OUT OF


    • Good out-of-the-box performance in ISF mode
    • Impressive calibration controls
    • Reference calibrated greyscale performance
    • Excellent video processing
    • Good motion handling
    • THX Certification for 2D and 3D
    • 3D performance is much improved
    • Freeview HD built-in


    • Mediocre and noisy blacks
    • Rather dull image, even for a plasma
    • Occasional instances of image retention
    • Average colour performance, even after calibration
    • Limited networking and streaming capabilities
    • No internet or Smart TV platform
    • Pentouch is a pointless gimmick
    • Input lag is very high
    • Energy consumption is quite high
    You own this Total 0
    You want this Total 0
    You had this Total 0

    LG PZ850 (50PZ850T) Full HD 3D Plasma TV Review

    The LG 50PZ850 has some excellent attributes and is capable of producing some very nice images but there is a feeling that useless features such as Pentouch are distracting the manufacturer from the task of making better TVs.
    Despite a make-over in terms of the cosmetics on the 50PZ850, there is the feeling that a lot of the technology involved in this display comes from last year. This suspicion is certainly evidenced by the menu system, lack of Smart TV, poor energy consumption, image retention and the layout of the rear connections. The picture quality is reasonably good with an excellent greyscale and video processing and as always LG includes a healthy set of calibration tools. However even they couldn't address the native colour gamut, which was under saturated in both red and blue. The 50PZ850 was also quite dim in both ISF and THX modes and the blacks were very mediocre and beset with noise.
    The good news is that the active shutter 3D performance appears to be much improved compared to the other LG plasmas that we have reviewed this year. The problems of excessive crosstalk appear to have been addressed and overall we found the 3D experience to be quite enjoyable. The poor blacks weren't an issue when wearing the active shutter glasses and in the 3D THX mode the image appeared reasonably bright, especially when compared to the 2D mode. LG's active 3D may not be as impressive as some of the other manufacturers but it is good to see them at least competing in this area again.
    As for the Pentouch function, aside from possibly in a school environment, we really can't see any use for this feature and we found it complicated to set up and clunky to use. All of the features found on Pentouch can be done on a PC faster and better and frankly we found it a complete waste of time. We would prefer it if LG just concentrated on producing TVs that delivered excellent pictures, rather than wasting their energy on pointless gimmicks like this. We would also like LG to address the issue of input lag, a measurement of 80ms is just too slow for any TV, especially a plasma.
    If you want Pentouch features we recommend you buy an 'Etch-a-Sketch' and spend the money you save on a dedicated TV. There are plasmas available that frankly offer better performance in both 2D and 3D and better value than the 50PZ850. We would really prefer it if LG concentrated on producing accurate TVs rather than pointless gimmicks.

    Suggested retail price when reviewed: £999.00

    The Rundown

    Contrast/Dynamic Range/Black Level


    Screen Uniformity


    Colour Accuracy


    Greyscale Accuracy


    Video Processing


    Picture Quality


    3D Picture Quality


    Sound Quality


    Smart Features


    Build Quality


    Ease Of Use


    Value for Money




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