Panasonic TX-P50GT50B 3D Plasma TV Review

2D Calibration

Note: Our Panasonic TX-P50GT50B review sample was calibrated using Calman Professional, the industry-leading video calibration software.


We were very happy with the picture quality of the [THX Cinema] mode, and to our eyes, it was fulfilling its intended purpose of presenting very high quality, accurate video with minimal fuss admirably (that is, after we’d made the two small adjustments of reducing [Sharpness] and shutting off the [P-NR]). We put it to science and measured some greyscale test patterns using our Klein K-10 probe:

Pre-calibration RGB Tracking
Pre-calibration RGB tracking and delta errors (dEs)

The performance on this particular Panasonic TX-P50GT50 unit is actually slightly better than the pre-calibrated images put out by the 50-inch VT50 panel we reviewed earlier this month. There was a subtle blue tint to shadowed areas and a slight excess of red in highlights. None of this had any huge impact on the picture quality of material we viewed. For an uncalibrated preset mode, this level of performance is excellent. As with the VT50, we happily watched the Viera GT50 in its [THX Cinema] mode, due to how small the errors were. This is a real step-up over much of the out-of-the-box accuracy of the 2011 Panasonic Plasmas (and also the 2012 ST50), which had a slight green tinge.

Since we have a probe, and since we have the menu controls to allow for a full calibration, we did just that, to see what the TX-P50GT50B is like when its operating at the best of its abilities:

Post-calibration RGB Tracking in [Professional1] mode
Post-calibration RGB tracking and dEs in [Professional1] mode

After adjustment of both the standard 2-point (RGB-Cutoff and RGB-Gain) controls, and the advanced 10-point controls, we were left with measurably perfect Greyscale tracking, with errors far below the threshold of actually being noticeable. As with the rest of the Panasonic plasma televisions, though, the Greyscale mixing varies depending on the overall brightness of a scene, so flawless accuracy in practice shouldn’t be expected, even although it’s possible to line calibration charts up perfectly. In fact, sometimes during calibration, we could see the picture become very subtly more red- or blue-tinted when the TV’s on-screen menus were showing. Unless you’re a colourist who works in the film industry who’s watching their own work, though, then we don’t think you’ll notice with actual content. The errors are basically at the level of being statistical rather than really visible.

We had to be careful during Greyscale calibration to prevent a red tinge from creeping in in shadowed areas. Using the 10 IRE [White Balance] adjustment couldn’t remedy this, because the tinge was creeping in at about 1 – 3 IRE. We had to use the 2-point controls to affect this, and then counter-balance with the 10-point controls to get a non-tinged result.


Gamma curve in [Professional1] mode Gamma tracking in [Professional1] mode
Gamma curve in [Professional1] mode Corresponding gamma tracking

As with the VT50, gamma tracking was highly accurate in the [THX Cinema] mode on the Panasonic TX-P50GT50, with an average gamma of 2.17 being measured across the 10 stimulus levels. In the [Professional] modes, selecting the “2.2” gamma option actually did result in an average of 2.16, which is excellent (with some older Panasonic plasmas, we had to select “2.4” to get something nearing 2.2 out of the screen). After calibration with the 10-point gamma control, we unsurprisingly measured an average gamma of 2.2, which is a gamma setting suitable for viewing environments with a little bit of ambient light present (which the GT50 does well under thanks to its Infinite Black Pro screen coating). There are 2.4 and 2.6 settings which are best suited to progressively darker environments.

Not surprisingly given their similarity, we also had to follow the same rule as we did on the VT50, and abstain from adjusting the 10% stimulus level to perfection with test patterns. If we did this, we ran the risk of causing small “floating gamma” issues (where the apparent lightness distribution shifts VERY subtly mid-way during a scene). We decided slightly lighter shadow details were a lesser evil than very rare and very mild gamma shifts.


The Panasonic TX-P50GT50B’s pre-calibrated colour was slightly worse than the VT50 we reviewed earlier, with a slightly oversaturated green primary. As with the rest of the lineup, red was a little orangey. Unlike the rest of the lineup, red was also too bright, resulting in a perceptibly less “rich” colour. Correcting these mild inaccuracies was an absolute cinch thanks to the [Colour Management] controls. We were left with measurably perfect performance after this process. Yes, we’ll be sharing settings, since these sorts of inaccuracies are somewhat applicable from unit to unit.

Post-calibration CIE chart in [Professional1] mode
Post-calibration CIE chart with reference to HD Rec.709
Post-calibration Luminance levels in [Professional1] mode
Post-calibration colour luminance (coloured bars = targets; black bars = measured values)

3D Calibration

Since Panasonic allied with Samsung and Sony to form a new standard for 3D active-shutter glasses, the manufacturers’ new glasses are now interchangeable with each other. We do have a pair of the new Samsung 3D glasses here, and can confirm that everything works as planned. However, since some retailers are bundling Panasonic glasses with Panasonic TVs, we decided to use the 3D eyewear that Panasonic provided for review purposes with the TX-P50GT50’s 3D mode, since that’s a more likely usage scenario. (Each pair of glasses has a slightly different colour tint to it).


3D Pre-calibration RGB Tracking
3D Pre-calibration RGB tracking and delta errors (dEs)

Pre-calibrated Greyscale tracking measured very similarly to last year’s GT30 in the “THX3D Cinema” mode, with a slight red tint overall, but green and blue excesses in shadowed areas. Not perfect, but much better than the first-generation 3D Plasmas and certainly decent. Seeing how specialised 3D calibration is, we imagine this is how nearly all viewers will watch extra-dimensional content on the Panasonic TX-P50GT50B.

3D Post-calibration RGB Tracking in [Professional1] mode
3D Post-calibration RGB tracking and dEs in [Professional1] mode

10-point Greyscale calibration is also available in 3D mode, so as with 2D, we achieved measurable perfection. Just like with 2D, some tints remain in practice, since the greyscale mixing deviates from spec with some real-world content. However, we were able to watch a film in the third dimension, deactivate the 3D mode and pull the glasses away from our face, and see a near-instantaneous comparison between the 3D and 2D display modes – and were left with nearly no complaints after calibration. The most jarring difference is the brightness loss imposed by the active-shutter glasses, but the overall image is very similar after adjustment.


Prior to calibration, the biggest colour errors in 3D were basically the same as in pre-calibrated 2D: an oversaturated green primary and slightly off-hue red (too orange). All were correctable with the Colour Management controls, except for the slight desaturation of blue which is barely visible.

3D Post-calibration CIE chart in [Professional1] mode
3D Post-calibration CIE chart with reference to HD Rec.709
3D Post-calibration Luminance levels in [Professional1] mode
3D Post-calibration colour luminance (coloured bars = targets; black bars = measured values)

Benchmark Test Results

Dead pixels Flashing red pixel in top right at some brightness levels
Screen uniformity Usually excellent, full white screen reveals very mild yellow-green tint in middle, with certain picture contents
Overscanning on HDMI 0% with [16:9 Overscan] set to “Off
Blacker than black Passed
Calibrated black level (black screen) 0.01 cd/m2
Calibrated black level (ANSI checkerboard) 0.013 cd/m2
Black level retention Stable, but care must be taken with 10 IRE setting in 10-point Gamma control to avoid introducing very subtle “floating gamma”
Primary chromaticity Excellent
Scaling Excellent
Video mode deinterlacing Very effective jaggies reduction
Film mode deinterlacing Passed 2-2 PAL and 3-2 NTSC tests
Viewing angle Excellent, screen filter blocks ceiling lighting, so vertical viewing angle lessened
Motion resolution Excellent (1080)
Digital noise reduction Present, optional
Sharpness Subtle undefeatable high frequency sharpening
Luma/Chroma bandwidth (2D Blu-ray) Full Luma, Full chroma with a 4:2:2 HDMI input, or with the [1080p Pure Direct] mode turned On otherwise
Image retention Very little, clears quickly
Posterization Very small “hardened” edges during fast motion
Phosphor trails Mild, some red trailing noted
1080p/24 capability No judder in 2D or 3D
Input lag 26ms compared to lag-free CRT
Full 4:4:4 reproduction (PC) Yes, only with YCbCr signal type, not RGB, some subtle “ringing” artefacts present on highly saturated transitions due to edge enhancement

Power Consumption

Default [Normal] mode (2D) 170 watts
Default [Normal] mode (3D) 222 watts
[THX Cinema] mode (2D) 191 watts
[THX 3D Cinema] mode (3D) 240 watts
Calibrated [Professional1] mode (2D) 175 watts
Calibrated [Professional1] mode (3D) 263 watts
[THX Bright Room] mode (2D only) 369 watts
Standby 1 watt

Measurements taken with full 50% grey screen to approximate real-world viewing.

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