Styling and Connections
The remote control that is provided with the P42GT20 is the same black plastic model that Panasonic include with the VT20 but it seems more in keeping with the P42GT20’s position as an entry level product than it did when included with a flagship model. Whilst the remote might not be winning any design awards, at least it fulfills its purpose and is well laid out, intuitive and comfortable to handle.
All the Panasonic displays for 2010 have come with an extensive selection of inputs and the P42GT20 is no exception. There are four HDMI v1.4 slots with three positioned on the rear of the panel and one on the side. HDMI 2 is the connection on the P42GT20 which allows the new audio return signal as part of the 1.4 specifications. This means that you can feed the TV direct from a Blu-ray player and then feed the audio back from the set to your HDMI v1.4 equipped AV receiver. Also on the back panel are two SCART connectors, one set of component RCA plugs, a VGA PC slot and an ethernet connection. There are also audio inputs and outputs using RCA plugs and an optical audio input. For the Freesat HD feed there is a satellite socket and for Freeview HD there is a standard RF socket.
On the side panel there are two USB inputs, a common interface card slot, a composite video input and further audio inputs along with an SD card slot and 3.5mm headphone jack. Finally on the side panel is the main power switch and basic volume and channel buttons.
I am still hopeful that Panasonic (and other manufacturers) will consider using downward facing inputs for the HDMI sockets and the power cable on their 2011 models. Such an approach would allow for better cable management and much easier wall mounting options which is how many of these new slimmer displays are installed.
There appears to have been some confusion with regards to whether or not the P42GT20 would come with any active shutter 3D glasses included. When it was first announced Panasonic said that due to the lower price the P42GT20 would be shipped without any glasses included, just as Samsung and Sony do with all their 3D displays up to and including their flagship models. However at the IFA show in Berlin the Panasonic representatives began to suggest that there might be glasses included after all and in fact there were a single pair in the box when I opened my review sample. Since my review sample was provided by an actual retailer rather than Panasonic themselves I can only assume that all the P42GT20s in the UK come with one pair of 3D glasses included. Unfortunately I can’t comment on the rest of Europe so for any readers outside the UK I would suggest you check with your dealer.
In addition to the P42GT20, Panasonic also launched their newly designed active shutter 3D glasses at IFA and clearly this is one area where Panasonic has been listening to user and reviewer feedback. The new design has fully enclosed sides that stop the reflections that plagued the original design and the nose bridge is fixed instead of detachable so it won’t fall off. The new design also comes in a number of different sizes (small, medium and large) which will allow you to choose the one that suits your head best.
Unfortunately the glasses included with the P42GT20 are the original design and therefore suffer from all the limitations that I’ve just mentioned. If I was being cynical I would say that Panasonic’s generous change of heart has more to do with shifting outstanding stocks of the older glasses than pure altruism but I guess a free pair is better than nothing. If when buying the P42GT20 there aren’t any glasses included and you are offered the option of buying some I would strongly recommend that you choose the new design.
Menus and Set Up
Like the EPG, the main menu system itself is bright, colourful, easy to read and quick to navigate. It offers three choices which are titled Picture, Sound and Set Up. In Set Up there are general controls such as Network Set, Timer and DivX VOD as well as a control called Advanced (ISFccc) that allows you to gain access to the Professional1 and Professional2 picture modes. Hidden away within the Set Up menu is an option called Other Settings and within here you will find three functions that it would have made more sense to include within the Picture menu. There is a control for setting the frame interpolation function which Panasonic calls Intelligent Frame Creation, although if the image being received is 24p then this function becomes the 24p Smooth Film mode. There is also a Resolution Enhancer control and finally a control for setting 16:9 Overscan. This last function is particularly important because only by setting it to off will you get accurate pixel mapping with no scaling and thus benefit from the full resolution of high definition sources.
The Sound menu offers three distinct modes which are Speech, Music and User, with User allowing you to customise the audio set up using an equalizer. There are also more general controls such as Bass, Treble and Balance as well as a setting for the distance between the speakers and the wall. Sound is another area where the P42GT20 differs from the VT20 with the P42GT20 only having two 10W speakers and no subwoofer. As a result the sound on the P42GT20 is somewhat lacking compared to its higher end stablemate but is still reasonable, especially when compared to some of the ultra-thin models.
The Picture menu offers a series of Viewing Modes which range from the eye blistering Dynamic to a THX preset that appeared to offer very good out of the box performance. There are also two ISF modes called Professional1 and Professional2 which allow access to additional Advanced Settings and can be locked. The idea is that the ISFccc modes provide a professional calibrator with the tools to accurately set the greyscale and colour gamut and then lock these settings so that they can’t be accidentally changed. The reason for two Professional modes is to allow the calibrator to create Day and Night settings, each of which is optimised for watching programmes under different viewing conditions.
The P42GT20 includes all the usual picture controls including a Contrast control for adjusting the luminance of the video signal, a Brightness control for adjusting the black level, a Colour control and a Sharpness control. The C.A.T.S. (Contrast Automatic Tracking System) is designed to adjust the Contrast setting from scene to scene in order to boost the contrast ratio numbers but this can cause fluctuations in the image and is best left off. Finally there is a P-NR (Noise Reduction) function that is designed to reduce compression artifacts but I found this control to be of no real benefit so I turned it off.
If the Professional1 or Professional2 mode is selected you will have access to the Advance Settings in which there are menus for White Balance, Colour Management and Gamma. The White Balance menu allows two point calibration of the greyscale, the Colour Management menu allows adjustments to be made to the Hue and Saturation of the three primaries and the Gamma menu allows a selection of different gamma curves.
Finally there are menus for setting up the 3D functions on the P42GT20. If you use a 3D Blu-ray player then the TV will switch automatically to 3D mode and this defaults to the Normal picture mode and this is important as light output is critical to get the 3D effect to work correctly. If you are using other sources for 3D material such as a Sky+HD box or a Sony PS3 then you will have to choose the correct options manually. Whilst you can select other picture modes including Cinema in lieu of the THX preset the best option is the Normal picture mode due to its increased brightness. You will also need to choose the correct 3D format, the choices here are Auto, Side by Side and Top and Bottom. The other settings available are Picture Sequence which reverses the left and right eyes, and Edge Smoother which applies some smoothing to the image but robbed the 3D image of finer details so I left it off. Once again hidden in the Setup menu under Other Settings there is a control called 3D 24p Film Display which allows you to increase the refresh rate on 24p 3D material from 24 frames to 48 frames per an eye.
When the VT20 was released earlier in the year Panasonic announced that unlike some of their competitors they would not be including a 2D to 3D conversion feature because they felt this was just a gimmick that produced awful 3D. I thought that Panasonic were correct about that at the time and I still do but obviously they felt the need to compete and as such have included a 2D to 3D Depth function in the 3D menu. However Panasonic’s attitude towards this feature appears to be to treat it like a ginger haired stepchild because they’ve hidden it away in the 3D menu and don’t mention it in any of their marketing literature.
The P42GT20 includes the 600Hz capability which as I mentioned in my review for he VT20 has caused some confusion as it is being marketed like the 100/200Hz features found on LCDs but is nothing of the sort. It actually refers to how the subpixels that make up the plasma image and it all comes down to the frame rate and how many subfields are used to make up one frame. These subpixels do not directly affect motion but rather make up the image being drawn on screen within each frame. Unlike LCD displays plasmas have no issues with motion blur so the inclusion of this 600Hz claim is nothing more than marketing blurb. I find it slightly amusing that plasma manufacturers feel the need to add these kinds of numbers in response to a feature that LCD manufacturers only introduced in an attempt to address a genuine weakness in that particular technology.
The P42GT20 also includes Panasonic's Intelligent Frame Creation which uses frame interpolation to automatically compensate for the picture frame rate thus removing judder and making images smooth and clear. Once again the inclusion of this function would also appear to be more marketing driven than anything else, as a plasma's fast response time means it doesn't suffer from the same motion blur problems that LCD displays do and thus this function is largely unnecessary and ultimately detrimental to the image.
When watching Blu-rays encoded at 24fps the P42GT20 has a 24p Playback function that will increase the frame rate to a more appropriate 96Hz which is a multiple of 24. There is also a 24p Smooth Film function that does something similar but includes frame interpolation and is best left off unless you want your film-like image to look more like video.
The P42GT20 includes VIERA CAST which is Panasonic’s version of internet TV and allows access to selected online content such as YouTube, Eurosport videos, Skype and Google’s Picasa Web Albums. It isn’t a web browser and is fairly limited compared to the internet functionality on some competitors’ displays but it does provide information such as weather and news and Panasonic is adding new content all the time.
Finally the P42GTT20 includes DLNA compliance for streaming photos, music and video, as well as DivX HD, VIERA Link, VIERA Image Viewer and Dolby Digital Plus decoding. This is another area where the P42GT20 is actually better specified than the VT20 because the SD card reader has been upgraded and is now compatible with 3D image files created by Panasonic’s new 3D camcorder or 3D digital cameras.
Measured Results Out of the BoxFor the purposes of these tests I used the THX mode which should represent the best pre-calibrated preset. I adjusted the Contrast and Brightness settings using a PLUGE pattern and whilst I able to set the Brightness correctly, it was obvious that the P42GT20 was clipping at peak white and there was nothing I could do to correct it. I left Colour on the middle setting and I set the Sharpness to zero and for the same reason turned the Resolution Enhancer off. The C.A.T.S. and P-NR controls were already turned off but I turned the Intelligent Frame Creation function off as well. The Gamma function was already correctly set to 2.2 and hopefully the actual curve will be close to that number. Please note that all testing was done after over 50 hours of continuous use.
Much like the greyscale measurements the colour gamut performance shown on the CIE chart was also good for an out of the box preset, with the P42GT20 measuring quite close to Rec709. The Luminance and Hue measurements are showing reasonably low deltaEs and although Colour is a little oversaturated in all three primaries and the brightness is also a little high; overall the colour reproduction is very good. The P42GT20 includes a Colour Management System so once again I would hope to make minor improvements with calibration.
Calibrated ResultsSince the P42GT20 shares the same menu system as the other Panasonic displays that I’ve calibrated I had the usual problem of the sliders for adjusting the CMS and White Balance appearing over the very point where the meter is trying to measure the IRE window. However since this was my fourth Panasonic review I was already familiar with a work around and thanks to the excellent out of the box performance the adjustments required were minimal.
As with all the Panasonic displays that incorporate a Colour Management System (CMS) there are only controls for Hue and Saturation whereas ideally you would want controls for Hue, Colour and Luminance. In addition the CMS only has controls for the primary colours (Red, Green and Blue) so you don’t have direct control over the secondary colours (Cyan, Magenta and Yellow). For this reason I found it difficult to get the colour gamut as accurate as I would like and I found the controls to be quite course. Whilst I was able to improve the Colour measurements compared to the THX preset I still felt the colours on the P42GT20 were a little too bright and slightly oversaturated, especially in red and green and this affected the overall DeltaE. This is still an excellent colour performance, but I think the inclusion of a more effective CMS would allow for even greater colour accuracy.
Panasonic are to be congratulated for including ISFccc controls but perhaps next time they could include 10 point greyscale calibration and a proper CMS with control over all three axies and all six colours which would bring them in line with many of their competitors.
Calibration for 3D viewing remains problematic in the absence of any established industry standards. The two main problems with 3D calibration are light loss and colour shift and thus any calibration approach needs to address these issues. The problem of light loss is best addressed by simply increasing the light output of the 3D display as much as possible without introducing any clipping or additional clipping in this case. Adjusting for the colour shift is a bit more difficult and ultimately the most effective way is to actually take readings through the 3D glasses in order to compensate for the colour shift they cause. THX has recently started to certify 3D displays so I will be interested to see how accurate and bright their 3D preset is.
Video ProcessingThe P42GT20 shares the same video processing technology with all the other Panasonics I have reviewed recently and as such displayed the same strengths and weaknesses.
Using both my PAL and NTSC HQV benchmark discs I first checked the SMPTE colour bar test which the P42GT20 easily passed, correctly scaling the full 576i and 480i images without any loss of detail or unwanted ringing. The P42GT20 also scored very highly in the jaggies tests on both discs as well as performing very well on the diagonal interpolation test, with two of the three moving bars appearing smooth and only the bottom most extreme bar showing very slight jaggies. The P42GT20 also had no problems in resolving all the fine brickwork in the detail tests on both the PAL and NTSC discs, as well as correctly displaying the waving flag.
As expected the P42GT20 did not perform so well in the film detail test and failed to correctly lock on to the image resulting in aliasing in the speedway seats behind the race car (for those of you who are familiar with the HQV test footage). The P42GT20 failed all the cadence tests and was unable to correctly detect either 2:2 (PAL - European) or 2:3 (NTSC - USA/Japan) as well as a number of less common formats. However the P42GT20 did perform well when displaying film material with scrolling video text, correctly displaying the words without blurring or shredding.
The P42GT20 also performed very well in most of the tests on the HQV Blu-ray 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 16:9 mode is correctly set with overscan off) and showed good scaling and filtering performance as well as good resolution enhancement. The P42GT20 also had no problems in showing video text overlaid on film based material.
The P42GT20 handled 24p content without any problems, although you needed to make sure that the 24p Smooth Film function has been turned off or you will introduce unnecessary artifacts and any film based images will have a video look to them.
I used my Spears and Munsil test disc to check the high and low dynamic range performance of the P42GT20, which with blacks showed picture information down to reference black (video level 17) so the performance here was very good. The headroom performance of the P42GT20 from reference white (video level 235) up to peak white (video level 255) was not so good with obvious clipping above video level 240, just as I had suspected. However the clipping was only slight and certainly wasn’t noticeable when watching real world material.
Overall this is an excellent set of results and the video processing of the P42GT20 is very good with the notable exception of film cadence detection which Panasonic really needs to correct and the slight clipping at peak white.
Flicker, Image Retention, Rising Black Levels and 50Hz Motion ArtifactsThese issues have all been covered in great detail in both my review of the P65VT20 and Phil’s review of the P50VT20 so I’ll only cover them briefly here.
Firstly I wasn’t aware of any flicker whilst reviewing the P42GT20 but I know that some people do see it and therefore I would recommend demoing the display first if you have experienced this problem in the past.
Secondly I was hardly ever aware of any image retention on the P42GT20 and on the rare occasion that I did notice it the retained image disappeared very quickly.
Thirdly Panasonic has still not officially commented in the UK on the reports of rising black levels on their 2009 models. However in the short period of time that I had the P42GT20 to test I experienced no such problems. I also experienced no such problems with the P65VT20 that I reviewed previously and I’m not aware of any problems being reported on the forums. For the time being all we can do is monitor this situation and report back if there is any news.
Finally there is the issue of artefacts related to 50Hz material and unfortunately this problem did affect the P42GT20. When I first received the P42GT20 for review there happened to be a Champions League match on ITV HD so I put it on and sure enough I could immediately see red, green and blue lines trailing the centre line as the camera panned across the pitch. The faster the pan the more obvious the trailing image, it almost looked like ghosting on very fast pans. I conducted the same moving zone plate test that I did with the VT20 and I got the same results, with artefacts at 50Hz but not at 60Hz and 24p. Now to be fair this problem is a lot less obvious on a 42” screen than it was on a 65” screen and many consumers may not even notice but it is there are once you know where to look it’s pretty easy to spot. I think the problem may be a result of the reverse subpixel processing that Panasonic developed for their 3D plasmas and it’s unfortunate that they have refused to answer our questions or to even acknowledge there is a problem. However I strongly recommend that anyone thinking of buying a Panasonic 3D plasma demo the 2D performance with a PAL DVD first.
Picture Quality - 2D
I found the viewing of actual material to be very good and 24p Blu-rays in particular looked spectacular with very accurate and detailed pictures that were free from judder. The same goes for Freeview HD which resulted in some equally impressive images, apart from the ocassional ringing caused by the 50Hz issues.
With standard definition material the Freeview tuner built into the P42GT20 did a good job considering how compressed a lot of the Freeview broadcasts are on some stations. The video processing also did an excellent job of scaling both PAL and NTSC DVDs but obviously the 50Hz issues still apply to PAL DVDs. The P42GT20's inability to correctly detect cadence didn't appear to create any obvious artefacts but Panasonic should still correct this problem soon, both Phil and I are getting sick of always having to point it out.
My PS3 outputs games at 60Hz and so I had no issues with 50Hz artefacts and the images the P42GT20 produced were bright and vibrant with no appreciable lag. Having said that I've started to find 2D gaming a little uninvolving and much prefer the immersive experience that 3D offers. I guess a lot of gamers are just waiting for that one killer 3D game to jump in, imagine Grand Theft Auto in 3D!
Picture Quality - 3D
I suspect that the P42GT20 is aimed primarily at the gaming market because not only is 3D gaming the area that is most likely to drive 3D sales but due to the slightly artificial nature of gaming it is also the most enjoyable. I also found myself sitting nearer to the screen when playing games which helped to create a more immersive experience on the smaller screen. I find that slower moving games tend to appear better in 3D because the brain doesn’t have time to register depth information when the images are moving too fast. I also think that games that use the additional depth that 3D provides in an imaginative way are also far more rewarding. Hopefully game developers will realise this as more 3D games are released onto the market
This brings me on to the main problem with 3D at the moment, a serious lack of content. Phil and I found it amusing that despite there being halls the size of Wembley Arena at IFA full of 3D TVs there were only three 3D blu-rays to buy at the huge A/V store across from our hotel. This situation will improve over the next month, firstly with the v3.50 software upgrade for the PS3 which Sony releases on the 21st of September; a previous upgrade allowed the PS3 to play 3D games but this new upgrade will allow it to play 3D Blu-rays. This will quickly be followed by Sky beginning its 3D broadcasts in October and Warners releasing a number of 3D Blu-ray releases in November. However the supply will remain limited and this situation is being exacerbated by the manufacturers paying different studios for exclusivity thus limiting the supply of content even further.
In a bid to find new 3D content I invited over a friend who had recently bought a 3D camera so that we could create some 3D material for the P42GT20. We looked at the still 3D photos he had taken using the SD card slot on the side of the P42GT20 and we watched some 3D video that he had shot using one of the HDMI inputs. The 3D material was surprisingly good and certainly a lot better than all the terrible 2D to 3D conversions that Hollywood is churning out.
The poor quality of a lot of 3D content is another problem that might well hinder the development of 3D as a platform. In Hollywood's greed to release ever more 3D content to the market, the majority of 3D films released are actually 2D to 3D conversions which never look as good as films shot with genuine 3D cameras. I actually watched some of the recent German 3D Blu-ray release of 'Clash Of The Titans' and it looked as bad as it did in the cinema. In fact it didn't look much better than watching the 2D version of the same film converted to 3D by the P42GT20 itself. This function has options for Min, Mid and Max in terms of the 3D effect that is added to 2D images but the overall impact is quite subtle and actually did work for short periods of time, then the software would become confused by something and the illusion would be ruined.
- Good black levels and dynamic range
- Good out of the box performance in THX mode
- Reference greyscale and very good colour reproduction when calibrated
- Freeview HD and Freesat HD built-in
- Reference level 3D performance
- Good build quality
- Excellent lag times for gamers
- Full ISFccc calibration controls
- THX Certified
- One Pair of 3D glasses included with the display
- The display has a processing issue with 50Hz material that results in artifacts
- Clipping at peak white video levels
- Due to the smaller screen size 3D viewing is less immersive
- PWM noise is visible when viewing close to the display
- Banding is sometimes visible with certain material
- Some users may see flicker from the image
- Still lacks film cadence detection
- Menu design gets in the way when calibrating
- CMS lacks full three way control for colour, hue and luminance as well as no control for secondary colours
- Greyscale calibration only uses as a 2 point control as opposed to the 10 point controls available on some other displays
- 3D glasses not that comfortable
- Extra 3D glasses are expensive
- Lack of content on Viera Cast
- Uses more power than its LCD rivals
Panasonic GT20 (TX-P42GT20B) Review
The P42GT20 is a good example of this because there is a lot about this display to recommend including the accurate colours and excellent greyscale, as well as the superb black levels, the reference 3D performance and the THX preset. Unfortunately there are also problems such as the issues with 50Hz, the clipping of peak white, the increased level of PWM noise and the smaller screen size robbing the 3D of any real impact.
This last point in particular is an issue for a 3D display and as a result I suspect the P42GT20 will mostly appeal to gamers because most games are at 60Hz which means the 50Hz issues are less of a problem and the combination of a reasonable price coupled with the minimal lag time and lack of ghosting provides a solid platform for 3D gaming.
Contrast/Dynamic Range/Black Level
3D Picture Quality
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