I mentioned calibration because that's how I compare all TVs -- only after adjusting their picture settings to the best of my ability (and since I publish my settings, readers can get their own TVs very close to what I see and compare in the review). But you might be wondering whether the GT50 can beat the ST50 before both are properly calibrated, since the GT50 has the THX modes and the ST50 does not. Comparing the GT50's best THX mode to the ST50's best mode, Cinema, I found that THX Cinema was slightly superior in grayscale and gamma, but dimmer and thus less punchy overall. Of course you can increase the light output of THX Cinema on the 55-inch GT50, eliminating that difference, but even after that, THX on the GT50 isn't that much better than Cinema on the ST50 -- certainly not worth the price difference alone.
For more details click the image above to see the picture settings used in the review and to read more about how this TV’s picture controls worked during calibration.
|Comparison models (details)|
|Panasonic TC-55PST50||55-inch plasma|
|Samsung PN60E6500||60-inch plasma|
|Samsung PN60E8000||60-inch plasma|
|Sony KDL-55HX850||55-inch edge-lit LED|
|Panasonic TC-P65VT50 (reference)||65-inch plasma|
Black level: The GT50's shade of black matched that of the ST50 nearly perfectly, with a deep, inky quality visibly superior to the Sony in letterbox bars and dark areas, for example the shadows and black clothing of Madam Heron (1:01:15) or the black screen areas during the shots of gears and levers (1:03:58) in Chapter 7 of "Sherlock Holmes: A Game of Shadows." The differences between the GT50 and the Samsungs were likewise vanishingly small and due to slight variations in calibration rather than any real performance differences. As I expected, the VT50 looked visibly darker than the others in these scenes.
Shadow detail, for example in Heron's hair, was also superb; nearly identical to the ST50 and PNE6500, and a bit better than the PNE8000. The latter may be due to a calibration difference or Samsung's processing, but aside from light output, it was the most noticeable difference among the plasmas in our lineup.
The main advantage of the GT50 over the Samsungs was in light output. Like the other Panasonics, including the 65-inch VT50, it achieved brighter whites in most scenes, which increased its apparent pop and contrast.
Color accuracy: At the risk of repeating myself I'll say that the ST50 and GT50 again looked nearly identical to one another in this category -- and superb overall. The skin tones of Moriarty and Irene in Chapter 2 (10:09) came very close to our reference VT50, if a bit less rich and saturated-looking. Again the GT50 held no clear advantage over the also-superb Samsung PNE6500, although I did prefer its image a tad to the E8000's bluer cast. The Sony LED, with its decidedly bluer cast overall, again fared the worst in the group. In dark scenes I also appreciated how the plasmas maintained their relatively neutral blacks and shadows, in contrast to the Sony which again got quite blue.
The parity between the GT50 and the ST50 lasted only as long as I kept both in the calibrated Custom mode. Switching to THX mode -- the GT50's supposed advantage over the ST50--made its color markedly worse, with a greenish cast especially visible in skin tones. THX also imparts a dimmer image, so all told it looked inferior to Custom after calibration on both TVs.
Video processing: Like its 2011 and 2012 brothers, the TC-PGT50 passed our 1080p/24 test on its 60Hz setting. It cadence was smooth and properly filmlike, indistinguishable from the look of the other sets in our lineup that handled 1080p/24 properly. As usual, I found that the 48Hz mode flickered too much to be watchable.
On the other hand, I did notice some artifacts from 1080p/24 sources in 60Hz mode. On the Digital Video Essentials test Blu-ray I noticed shifting lines and minor instability in the downtown Philadelphia buildings during an upward-facing pan. I also noticed an instance in "Sherlock" at 38:40 in which the bookcase in the background flickered a bit during a quick pan. These types of artifacts are rare, and in my book easily worth the trade-off to get true film cadence, but of course the Samsungs and Sony didn't show them at all.
Panasonic's Motion Smoother delivers three options, Weak, Medium, and Strong, and as usual I found all three relatively distasteful and preferred to leave the setting off.When engaged, Motion Smoother caused an improvement in motion resolution in our test pattern (see the Geek Box), but it's not worth the smoothing in our book because any blur was impossible for us to discern with real program material.
I was curious whether the dual-core processor helped with smoothing related artifacts but one quick test seemed to indicate it didn't. When the red car takes the corner at 3:43 from "I Am Legend," I saw the same breakup along its trailing edge in dejudder mode with both the single-core ST50 and the dual-core GT50. Similar artifacts caused by quick-moving onscreen elements also looked the same on both sets.
The GT50 passed our 1080i deinterlacing test with 3:2 pull-down set to On, but not when I used the default Auto (and, despite what the menu explanation says, this setting does affect HDMI sources).
I mentioned in the VT50 review that its processing extras, said to improve motion resolution and shades of gradation over the ST50, yielded no improvement in my tests. I didn't run all of these tests on the GT50, but since it shares those extras with the VT50, I feel safe assuming it it also offers negligible improvement. I also did not test the 1080p Pure Direct function since the content it requires to realize any benefit (4:4:4 uncompressed component video) is rare.
Uniformity: I don't usually include a uniformity section in my plasma reviews since it's usually perfect for all practical purposes. I have seen some complaints online, however, from people who say their 2012 plasmas with the louvre filter (ST50, VT50, and GT50) show the so-called "dirty screen effect" -- in this case faint vertical bands, smudges, or other screen structure visible in flat fields of one color, especially during camera movement.
I don't consider DSE an issue on any of the TVs in the lineup. Comparing the Panasonic plasmas to the other sets in my lineup for this review, the Samsung 6500 and Sony LED actually showed the most visible screen structure during a hockey game -- the classic torture test for DSE -- but I still wouldn't classify the effect as distracting. Of course I don't know whether other samples of Panasonic plasmas have worse DSE; I can only speak for the ones I was sent by the company.
Bright lighting: The GT50 shares the same louvre filter with the ST50, and under the lights the two look virtually identical. Both do a very good job of preserving black levels -- about equal to the Samsung 6500 but better than the 8000 by a hair. The VT50 and the Sony were the best in this department. Reflections were also quite dim; again not as good as the VT50 but a bit better than the rest.
3D: For my 3D test I engaged THX Cinema mode and spun up "Hugo." The GT50 performed the same as the ST50 in what I consider the most important aspect of 3D picture quality for an active 3D TV: reduction of crosstalk. To get the best performance in this area it's important to change the TV's "24p Direct in" setting from the default 60Hz to 48Hz.
Afterward doing so the GT50's crosstalk performance was quite good. The ghostly double-image was invisible in most scenes, and in especially difficult sequences like Hugo's hand as it reached for the mouse (5:01), the tuning pegs on the guitar (7:49) and the face of the dog as it watches the inspector slide by (9:24), it was relatively faint. Compared with the PNE6500, crosstalk was about the same; the Sony HX850 was worse and the Samsung PNE8000 was the best of all, with the faintest ghosting in my lineup.
Aside from crosstalk, the image in THX 3D Cinema was very good. Black levels appeared about as deep, and shadow detail as realistic, as on the ST50, but color was a bit better. The black areas and shadows on the ST50 appeared bluer, and while brighter areas and skin tones were very close, they also looked a bit better (less blue) on the GT50.
Color and shadow detail were superior to the default Movie mode of the Samsung E8000. The Samsung also seemed to be doing some edge enhancement. I assume all of these issues can be improved by calibration however, and even if they can't I still liked the 3D image from the Samsung, with its slightly less obvious crosstalk, better than the GT50's.
Panasonic's standard 3D glasses for my review fit better than the Samsungs and provided marginally better performance since they enclosed my eyes better. Check out my comparison and reviews for more.
Power consumption: No surprises here: the GT50 is an energy hog compared with LEDs and similar in power use to other plasmas. On the comparison chart below the 60-inch Samsung might seem to have an efficiency advantage over the 55-inch Panasonics, but that's due to its lower light output even after calibration. In the Juice Box, the GT50's seemingly solid numbers for the default Standard picture mode are due, as usual, to a vanishingly dim picture.
This year, due to the hard cap of 108 watts for any sized TV imposed by Energy Star's latest 5.3 specification, all 55-inch and larger Panasonic plasmas fail to earn the blue sticker.
Editors' note: CNET has dropped TV power consumption testing for 60-inch or smaller LCD and LED-based TVs because their power use, in terms of yearly cost, is negligible. We will continue to test the power use of larger LCD or LED models, as well as all plasma OLED models.
|Panasonic TC-P55GT50||Picture settings|
|Picture on (watts)||132.66||251.04||N/A|
|Picture on (watts/sq. inch)||0.1||0.19||N/A|
|Cost per year||$29.18||$55.13||N/A|
|Score (considering size)||Poor|
|Black luminance (0%)||0.0051||Good|
|Near-black x/y (5%)||0.3086/0.3187||Good|
|Dark gray x/y (20%)||0.3096/0.3259||Average|
|Bright gray x/y (70%)||0.3133/0.3289||Good|
|Before avg. color temp.||6632||Average|
|After avg. color temp.||6452||Good|
|Red lum. error (de94_L)||1.8722||Average|
|Green lum. error (de94_L)||1.051||Good|
|Blue lum. error (de94_L)||2.8183||Average|
|Cyan hue x/y||0.223/0.3356||Good|
|Magenta hue x/y||0.3243/0.1541||Good|
|Yellow hue x/y||0.4229/0.5116||Good|
|1080p/24 Cadence (IAL)||Pass||Good|
|1080i De-interlacing (film)||Pass||Good|
|Motion resolution (max)||1200||Good|
|Motion resolution (dejudder off)||900||Good|