Panasonic Viera TC-P50G20 Plasma HDTV HT Labs Measures

HT Labs Measures

Black: 0.008
White: 30.22

All of the measurements here, unless noted otherwise, were taken in the THX Picture mode, through an HDMI input, with the Contrast control on 49, the Brightness on 60, and the other adjustments set as required for the most accurate image in a darkened room.

If judged in comparison with the Panasonic HDTVs we’ve tested over the past two years, the TC-P50G20’s black level and contrast ratio are merely average—although that still means comfortably better than average by overall industry standards. Two previous Panasonics have measured better, but one of them was the admittedly larger and far pricier ($10,000) Premier TH-65VX100U.

Both the Before Calibration and After Calibration color-tracking measurements were performed in the THX mode. The Before Calibration result, out of the box, was only fair, with Delta E readings that ranged from 1.4 to 5.8. After calibration, the maximum Delta E measured 3.6 at 30 IRE on the dark end, 3.6 at 100-IRE peak white, and under 2.0 at all other points.

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The Custom Picture mode offers user menu white-balance controls for calibration, while the THX mode does not. To calibrate the THX mode, you must enter the service menu. That’s what I chose to do for the results shown here, primarily because the THX mode has the most accurate color gamut. The black triangle indicates the HD standard. The THX mode closely matches the standard; the Custom mode’s gamut (not shown) is too wide—an all too common practice in HDTVs these days. A wider than standard color gamut is not a plus, since HD source material is produced to the HD standard (or should be). If it is not played back using that standard, the colors will not be accurate.

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While a competent calibrator must use the service menu to get around the lack of user menu white- balance controls in THX mode, there is no alternative to the lack of Gamma options in THX. The THX mode’s fixed gamma measured a low 1.98 and 2.14 from 20 IRE to 80 IRE, decreasing to 2.31 at 90 IRE. This means that the image will be lighter than ideal in ways that the standard user controls cannot compensate for. In practice, the low gamma wasn’t obvious to the eye (the ideal gamma ranges from 2.2 to 2.4, the actual value again depending on who you ask). I didn’t find the Gamma options in the Custom menu to be of any real benefit, and they produced some bizarre results. For example, a Gamma setting of 2.6 ranged from a high of 2.19 at 20 IRE to 1.3 (that’s not a typo) at 90 IRE. The fixed gamma in the THX mode produced the best subjective result, despite its slightly low measured values.—TJN

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