Panasonic TX-P42UT50B Plasma 3D TV Review

Note: Our Panasonic TX-P42UT50B review sample was calibrated using Calman Professional, the industry-leading video calibration software.

Once we selected the [True Cinema] mode, the TX-P42UT50 still needed some basic adjustments made to heighten image quality and accuracy. [Sharpness] comes set in a way which adds edge halos; turning it to its minimum setting removes this artefact (although if you’re sitting farther from the screen, you might want to notch it up a little). [16:9 Overscan] is enabled in the default state, which crops off the outer edges of the picture and reduces quality since it involves a scaling process. Apparently some satellite channels still broadcast pictures with garbage at the outer edges, which is what this option is for, although this just seems nonsensical for HD broadcasting in 2012. [P-NR] also had to be shut off to avoid introducing mild noise reduction artefacts.

Greyscale

With just these basic adjustments made (which reflects the state that many UT50s will stay in, since we imagine few people will have a £500 TV calibrated, unless they’re DIYers who have the hardware, software, and time to dedicate to the learning curve), the image quality was good, although images lacked punch and depth (when viewed in our moderately-lit test room). We found out why after running some pre-calibrated measurements, using test patterns and our Klein K-10 probe:

Pre-calibrated Gamma tracking in [True Cinema] mode Post-calibrated Gamma tracking in [True Cinema] mode
Pre-calibration gamma tracking (2.2) Post-calibration gamma tracking (2.4)

The dip downwards on the left (pre-adjustment) chart shows that gamma is measuring too low from 0% to about 50%. In other words, the TX-P42UT50B, in this basic setup, was displaying shadowed areas with too much brightness, causing the image to look slightly “milky” and without as much punch as would be ideal.

For the most part, gamma tracking was too low, meaning that the TXP42UT50 was exaggerating shadow details – making parts of the image which should be near-black into a lighter grey. It’s surprising that Panasonic would ship the television like this, because since it uses their acclaimed PDP technology, the UT50 is capable of producing considerably richer images with deeper blacks than nearly every LCD-based TV it competes with.

Not to worry though, because the fix is simple. We entered the [Gamma] menu (which appears after turning on the [advance(Calibration)] option) and selected the highest possible gamma setting – “2.6″ (which actually measured closer to being 2.4 – 2.5 for the most part). This greatly enhanced the depth and punch of the TX-P42UT50′s output, however, users watching in brighter rooms might well appreciate the default setting with its boosted shadow details. A display gamma of 2.4 is what’s used in critical Hollywood image checking, and is suitable for darker rooms (like the UT50 itself). If you’re in a brighter environment, setting [Gamma] to “2.4″ – which actually results in something closer to 2.2 – should be more appropriate.

With this settled on, we ran some measurements to see how accurately the Panasonic TXP42UT50B was colouring grey shades.

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

Like the ST50 series, the answer is: “with slightly too much green”. A slight green tint was visible to us, but as always, we need to remind readers that we’re in the position of looking at calibrated screens all day, every day, and the image will look completely normal to nearly all users. The greyscale linearity was excellent, too, which is crucial for believable images.

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

Using our probe and measuring software, we adjusted the controls in the [White Balance] menu while measuring grey test images and managed to achieve a more neutrally tinted result. Remember, it’s not possible to make any meaningful adjustment to this control with your eyes alone, nor is it possible to copy the settings from someone else’s TX-P42UT50 into yours, since each panel is unique and needs to be precisely measured for real improvements in neutral colours to be possible.

The end result on our review sample was excellent, with slightly green-tinted shadows being the only point of contention. Grey shades from 20% onwards appeared completely tint-free to the eye. If you’re looking to own a calibrated HDTV and want one which avoids issues like this, you’ll need to step up to the GT50 or VT50 series, which feature 10-point greyscale calibration, allowing more precise adjustments to be made.

Colour

Before any adjustments were made, colour reproduction was already good enough to give natural-looking images, with only a slightly too orange red point working against accuracy. As with all Panasonic plasma TVs, when we measure coloured windows (which feature a measuring patch of colour in the middle of the screen, surrounded by black edges), our calibration software reports colours that are overly bright. However, measuring with APL test patterns reports that things are more or less in spec. This suggests that the exact colour accuracy is never 100%, and there’s room for colours to appear slightly too “hot”, depending on the programme material.

Although it’s a measurable and repeatable quirk, we’ve never found it to present much of an obvious problem in pratice, for two reasons: first, the inaccuracy isn’t huge, and second, it appears to only crop up when most of the video image being displayed is dark – and very dark scenes in films and TV shows rarely feature highly saturated colours.

Since the TX-P42UT50B is equipped with full colour controls, we made use of these to perfect the screen’s output. As with the ST50 series, Panasonic hasn’t offered any hue, saturation or luminance controls over the secondary colours: cyan, magenta and yellow. In theory, these shouldn’t even need adjustment, since they’re mixed from the primaries (red, green and blue). Since the basic [Colour] control acts as a global control over the luminance levels of all six colours, we adjusted this down by one notch so that the secondaries measured as accurately as possible. That made red, green and blue too dull, so we used the luminance controls that are provided for these colours to turn them back up.

The result is supremely accurate colour:

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

Saturation tracking measurements are something we’ve only had access to until recently, and give us a fuller understanding of whether or not the hue and saturation of the colours stay on target at different levels of saturation. As you can see from the above result, the TX-P42UT50 continues Panasonic’s excellence in this area. Their entire 2012 lineup produces extremely accurate colours at all levels, with the UT50′s inaccuracies being at a level below that which presents a visible flaw.

Colour saturation tracking
Post-calibration colour saturation tracking

Benchmark Test Results

Dead pixels None
Screen uniformity Essentially perfect, almost no noticeable colour shifts on grey screen
Calibrated black level (black screen) 0.009 cd/m2
Calibrated black level (ANSI checkerboard) 0.009 cd/m2
Black level retention No “floating blacks” encountered
Primary chromaticity Excellent
Scaling Excellent
Video mode deinterlacing Effective jaggies reduction
Film mode deinterlacing Passed 2-2 PAL and 3-2 NTSC tests in SD and HD
Viewing angle Perfect (plasma with no screen filter)
Motion resolution 1080
Digital noise reduction Optional, not forced
Sharpness No ringing noticed with content, see notes
Luma/Chroma bandwidth (2D Blu-ray) Full Luma, Full Chroma
Image retention Very little
Posterization Mild, though worse with poor source
Phosphor trails Very mild
1080p/24 capability No judder in 2D or 3D
Input lag 16ms compared to lag-free CRT
Full 4:4:4 reproduction (PC) No, 4:4:4 input subsampled

Power Consumption

Default [Normal] mode (2D) 103 watts
Calibrated [True Cinema] mode (2D) 145 watts
Default [Normal] mode (3D) 135 watts
Calibrated [True Cinema] mode (3D) 192 watts
Standby 1 watt

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