Panasonic TX-P50GT50B 3D Plasma TV Review

Black Level

Full-screen black on the Panasonic TX-P50GT50 measured at 0.010 cd/m2, which is visibly the same as the 0.009 cd/m2 we measured from the ST50 and VT50. This means that the Viera GT50 plasma TV produces one of the deepest black levels on the market.

As usual, we also tested with the ANSI checkerboard pattern, where the middle black patch surrounded by full-white boxes measured 0.013 cd/m2, barely higher than the full-screen result.

Black level is hugely important to any display. Darker blacks mean that dark scenes will appear with more realism and “pop”, and colours will appear more saturated, vibrant, and realistic. It’s also important to know that black level can be faked by screens with lesser abilities in this area. For example, nearly all LED LCD TVs we’ve seen shut the light source off when a black screen is input – literally shutting out the lights to fake a darker picture. We say “fake” because this trick is of no use whatsoever for watching anything other than a black screen. In fact, pressing PAUSE on your disc player to display its on-screen display is usually enough to get these LED LCDs to light up again, revealing their true dark performance. None of the Panasonic plasma TVs do this – they keep the screen running even with a fully dark video input.

Peak White Output

As with the VT50, the Panasonic TX-P50GT50B has a luminance cap in its [Professional] picture modes (the ones that offer the full range of calibration controls). Unlike the VT50, the GT50 managed to produce 90 cd/m2 of light with a 100% white windowed test patch, whereas the VT50 managed 80 cd/m2. We wonder if that has anything to do with the different screen filter, “Infinite Black Ultra”, on the VT50. The cheaper TX-P42ST50 can still produce brighter and slightly punchier images than both of them, though, hitting around 130 cd/m2 easily (we’re not sure if the 50″ ST50 is the same, but we’d guess that it is, seeing as the light output cap seems to be consistent with the inclusion of the “Professional” picture mode, compared to the ST50’s “True Cinema”). It’d be good if Panasonic could un-cap these modes with firmware updates; in the current state, raising the [Contrast] control is useless in the Professional modes and only serves to crush out whiter-than-white details in the video signal, without actually raising the light output of the panel by any real amount. The ST50’s [Contrast] control does crush whiter-than-white details if turned up fully, but does also increase panel light output.

On the TX-P50GT50, the [THX Cinema] mode’s [Contrast] control isn’t locked, and it behaves like the ST50 in this regard. That means that in the [THX Cinema] mode, we had no issues hitting 130 cd/m2, which is better for brighter rooms. However, video enthusiasts take note that the THX modes have no in-depth calibration controls (although since they’re pretty accurate, anyway, that might not be troublesome for most users – at least not when the plasma panel is new).

There is also a [THX Bright Room] mode, which some have suggested should basically act as a surrogate for ST50-style controllable light output. We don’t agree. While the THX Bright Room mode (which uses a combination of a very low gamma setting and high panel light output) works well in a sun-drenched room, it’s overkill for users who just want a brighter image in moderately-lit viewing environments, due to its very low gamma setting (which is fixed). If you engage this mode in a standard viewing environment, the picture will look very washed out. That’s not a criticism of THX; since it’s obvious that this mode was not designed for “normal” viewing environments (if there’s such a thing as “normal”!).

Motion Resolution

We noticed absolutely no difference in motion quality when compared to the VT50, which again, makes sense since both are specced with the same “2500hz Focused Field Drive”. In turn, this barely looked any different from the ST50, which in European countries, features a “2000hz” version of the same technology. If we were to compare 2000hz vs 2500hz versions side by side we’d perhaps see some differences, but whatever they are, they’re subtle enough to have passed us by with back-to-back in-depth reviews. All three portray absolutely excellent motion quality, and compared to last year, the dithering noise (a standard part of Plasma display technology) is disguised in a much better way compared to previous models. Phosphor trails (coloured streaks in the image) are very small. 60fps test clips (they’re 60 fields per second, not 60 frames, since we’re in-depth!) and 60fps video games all displayed wonderfully on the TX-P50GT50B, with only a light coating of dithering noise being visible during fast motion.

The Panasonic TXP50GT50 resolves all 1080 lines of a scrolling resolution test chart (from the FPD Benchmark disc). So do newer LED LCD screens, but the GT50 Plasma still looks sharper during motion, due to the way that a plasma television’s screen drawing method interacts with the human eye and brain.

The only minor motion problem left over is some subtle coloured false contouring which can appear with certain combinations of colour, during very fast camera pans. We spotted this a few times during high-motion video content, such as documentaries, and very occasionally with 24p film material. All in all, the motion quality is outstanding. It’s very sharp and also largely free of artefacts.

If you’d like to read our raw, first-time impressions of how the 2012 Panasonic Plasmas have improved on the motion quality of the 2011 range (which was already excellent), read the Motion Resolution section in our TX-P42ST50 review.

Resolution and Frequency Response

Just like the TX-P50VT50, we found that the Panasonic TX-P50GT50B applies subtle undefeatable sharpening to all incoming images, which is presumably what they market as the “Edge Ultra Resolution” feature. We discovered this by looking at a Luma Zone Plate test pattern, which shows with significant moire artefacts (as well as a bizarre “four leaf clover” shape in the middle) on the GT50 and VT50, even when the [Sharpness] control is set to its lower positions. There’s no way of turning this feature off, not even if [1080p Pure Direct] is selected, but as with the VT50, we couldn’t see it making any effect on video images – positive or negative. There are no glowing outlines around text in menus, for example. Very fine pixel details from a computer source can end up looking ragged, though, so the undefeatable processing isn’t entirely invisible with real-world material.

Again, although it doesn’t cause any problems with video images, we really do think Panasonic should let the user turn it off, at least in the [1080p Pure Direct] mode. Truth be told, we’re scared that next year’s models will feature a more extreme version of the same thing.

Screen Uniformity

If we peered very closely, we could spot a slight yellowish cast in the middle of the screen (relative to the edges) during the APL Brightness/Contrast pattern on the AVSHD test disc. This means that the GT50 behaved essentially the same as the ST50 in this regard. It’s likely that if clear differences are visible between panels on the assembly line, then Panasonic will keep the best ones for the most expensive VT50 series (indeed, we saw no uniformity problems on that display at all). However, the slight deviation in greyscale mixing across the panel surface never became visible with any content that we watched during the review process, and is absolutely nothing compared to the uniformity problems seen on even the better edge-lit LED LCD TVs.


Once again, the Panasonic TX-P50GT50 exhibits near-identical tri-dimensional performance to the VT50. Noticing a pattern yet? Just like that series of plasmas, the GT50 excels at producing a 3D experience that’s nearly free of crosstalk double-image artefacts, but the overall picture quality is lower than the dizzying heights of the 2D display mode, with lower brightness, coarser gradation, and in some shades of the picture, lessened resolution. It seems that some of the sub-fields which make up a plasma frame are being drawn at half vertical resolution, for reasons which we’re not entirely sure of. The end result is that while the extra-dimensional images still look sharp, some moving objects can look slightly jagged at times.

As usual for a Panasonic 3D TV, the TX-P50GT50B outputs every single type of 3D content with “cinema quality” motion: it can show judder-free 3D images without having to resort to motion interpolation (although the latter is an option for users who want to enable it). 50hz, 60hz, and 24hz input are all output by the plasma display panel at a multiple refresh rate of the input, leading to no motion stuttering. (Actually, because of the workings of the plasma TV, the motion quality as actually probably slightly better than most digital cinema projectors, which are totally different devices).

Standard Definition

We were about to indulge in a shameless copy and paste from our review of the Panasonic VT50 plasma here, but in fact, the TX-P50GT50’s SD performance is different. What changed? The film cadence detection. On the VT50, we were surprised to see that the TV failed to detect film material in a PAL video signal, showing jaggies during the 2-2 cadence test. This test passes on the GT50. Puzzling…

Asides from that, it’s business as usual, with excellent diagonal filtering (jaggies avoidance) and crisp, clean scaling. That means that we have no real criticisms of the TX-P50GT50B’s SD handling at all – standard-def images look as good as the source material allows.

High Definition

Not surprisingly, the Panasonic GT50 presented one of the best 2D HD images we’ve seen from an HDTV recently. There is so little wrong with it that’s it’s actually hard to write about.

The blacks are deep, the colours are accurate, the greyscale and gamma are accurate enough with real-life viewing to present images that aren’t obviously discoloured, motion artefacts are rare, there’s no motion judder, there’s no film grain blurring to reduce the fine textures in the best HD (Blu-ray) content, there are no real viewing angle limitations worth mentioning, there are no uneven patches of light in any area of the panel, and the anti-reflective screen coating allows for much of the high contrast performance to be enjoyed in your averagely lit living room.


So, what problems do exist? Well, even although motion is far ahead of most competing HDTVs on the market (which are using LCD technology), it’s not entirely free from artefacts, with very fast motion sometimes revealing coloured contours and lessened gradation. That’s really only an issue with 50i and 60i high-motion video content like TV sports and other video camera material, with the 24fps frame rate of film not being high enough to reveal many issues.


Input lag measured at 26 ms in the “Game” picture mode, which is slower than the leaner ST50 series, but still a result which provides very fast and immersive gaming. This mode switches to a different panel drive mechanism, and also makes sure that any inherently laggy processing (such as [Intelligent Frame Creation]) is disabled and can’t be enabled. The image quality takes a subtle hit, with gradation quality being lessened. Especially in dark areas, fine details are less cleanly rendered, instead being blanketed with some slight panel generated noise (since the plasma can’t produce as many shades in the faster “Game” mode). That’s fine by us, since the picture quality is still very good, and the most important thing for many types of game is a fast response. There is also no limitation to the workings of the [Contrast] control in Game mode, you can set the panel light output to a wide range of levels.

We usually discuss image retention in the gaming section, because video games are the example we traditionally associate with static on-screen graphic elements. Like any Plasma television, the Panasonic TX-P50GT50B will retain images if they’re displayed for long enough, but like all modern Plasmas we’ve reviewed, the effect is temporary and eventually fades through normal usage, which can be sped up by running the “Scrolling bar” pattern. In fact, we find that TV news channels are the biggest offenders in this area. BBC News, EuroNews and France 24 (to use a few satellite exmaples) are all guilty of including 100% opaque (no transparency) coloured logos with bold white text. Why TV networks continue to be this irresponsible is completely beyond us. Perhaps once OLED TVs appear on the market they’ll be more careful…

Online Features

We’re not sure what Panasonic’s internet platform is called: in 2009 it was VIERA Cast, later it was VIERA Connect, and now the button on the remote simply leads “INTERNET”. In any case, it compares well with competing solutions, with apps for Skype, BBC News, BBC iPlayer, and Netflix all being present.

Viera Connect

Since the Panasonic TX-P50GT50 has been with us for a while, we’ve had the chance to test out the Netflix app especially. It’s been suggested that Blu-ray Disc faces competition from movie streaming services such as this one, but honestly, we don’t see why the two cannot happily co-exist. Netflix is just another way to watch films and TV shows, and it’s a very convenient one at that. The introduction of satellite channels showing non-stop films wasn’t viewed as a threat to physical media (which at the time would be VHS), so why should Netflix be? It can’t hope to compete with the image quality of Blu-ray, given the current speed of internet connections in most Western countries, not to mention the bandwidth caps set in place by ISPs. Even if those issues were to be resolved, it would still be in streaming services’ best interests to reduce bit rates to a low minimum acceptable level, since bandwidth equals money – unlike on Blu-ray, where disc authors have a 12cm plastic disc and a 40mbps maximum video bit-rate to spend with no financial penalty (assuming the number of disc layers is the same, it costs the same to manufacture a half-full BD as it does to manufacture one that’s filled to the edge).

Netflix and other streaming services arguably have much more in common with cable/satellite pay-per-view services than they do with Blu-ray. Streaming services offer huge convenience, no physical product, “good enough” picture and sound quality, no extra features, and in the case of Netflix, are subscription-based. That contrasts starkly with Blu-ray, which has the potential for near-studio-master quality, surround sound, extra features, etc purchased on a per-title basis. The convenience of Netflix is outstanding (although the lineup in the UK is limited, unlike Blu-ray Discs, most of which are region free and can be bought from anywhere in the world), and it’s a great addition to the Panasonic internet platform.


The Panasonic TX-P50GT50B is the third in a series of very similar and very excellent Plasma TVs we’ve reviewed from the Japanese manufacturer’s 2012 range. Like nearly every Plasma television the company has released, it represents outstanding picture quality and value for money. If you’re familiar with their 2012 Plasma lineup, think of the GT50 as a VT50 with a slightly plainer design and a less cutting-edge anti-reflective filter. Those are basically the only significant differences we could see, and whether you end up with an ST50, GT50 or VT50, it’s win-win, because they’re all brilliant.

The TX-P50GT50 excels in nearly every usage scenario that we can think of. The only situation in which we’d advise against its purchase would be for an exceptionally bright room, where an LED LCD TV stands a better chance at being able to produce a picture that’s bright enough to compete with ambient light. However, for the average viewing environment, a Plasma such as the Panasonic GT50 will provide superior picture quality to the LED LCD competition.

For this reason, we’d say that most of the TX-P50GT50B’s competition comes from elsewhere in the Panasonic Plasma range (although Samsung has produced some very good Plasmas recently, too – and we look forward to seeing their 2012 models). Is the GT50 worth the extra over the already excellent ST50? You decide: the GT50 and VT50 are both slightly dimmer than the ST50, although probably due to their THX Certification, they produce better picture quality out of the box, whereas the ST50’s slight green tinge needs to be adjusted out by an experienced calibrator for the best quality. The GT50 does also feature slightly better overall picture quality than the ST50, with more shades of gradation, although the difference is pretty subtle in our opinion. And, the ST50’s picture quality could be judged better by many due to the fact that it can go brighter in its most configurable picture modes.

During the time the TX-P50GT50 has been with us, we incidentally calibrated some other LED LCD televisions and ran them side by side with the GT50. After a Panasonic Plasma binge, we’re glad that we did, because it’s a sobering reminder of the competition. Many LED LCDs certainly provide good picture quality, and we have no bias towards one display technology or the other – if an LED LCD was to come along that had the same uniformity, freedom from viewing angle restrictions, and black depth, we’d be all over it – but no such (consumer?) LED LCD display exists.

Its suitability for a wide range of applications, excellent image quality, and value for money mean that the Panasonic TX-P50GT50B gets the same rating as its ST50 and VT50 siblings:

Highly Recommended

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