Panasonic TC-P50GT30 3D Plasma HDTV HT Labs Measures
HT Labs Measures
Full-On/Full-Off Contrast Ratio: 3,581:1
All of the measurements here, unless noted otherwise, were taken in the Cinema or THX Picture mode, in 2D, through an HDMI input, and with the set adjusted as needed for the most accurate image in a darkened room.
Delta E, a number referenced in the following discussions, is a figure of merit that indicates how close a display’s color tracking comes to producing an ideal white balance (a specific 6500K point on the CIE color chart known as D65 or D6500). The lower the Delta E number, the better. Ideally, the Delta E will be identical at every brightness level, but in practice, it always varies. Experts generally agree that levels below 3 or 4 indicate a result that is visibly indistinguishable from perfect color tracking.
The full-on/full-off contrast ratio was calculated from a measured peak white level of 28.65 foot-lamberts and a black level of 0.008 ft-L. The latter was comparable to the black level on the ST30 and slightly inferior to the VT30.
The gammas in both the Cinema and THX modes are fixed with no user settings to change them. The TC-P50GT30’s gamma averaged 2.01 in its Cinema mode and 1.85 in THX. Both are lower than the desired 2.2 value, but the Cinema gamma is significantly closer. Therefore, the TC-P50GT30 was calibrated and evaluated in the Cinema mode. Even then, the TC-P50GT30’s lower gamma was subtly visible in a side-by-side comparison with the VT30 and ST30 (the gammas of the latter two sets averaged just below 2.2).
Before calibration, the TC-P50GT30’s Cinema mode color tracking was the worst of the group, with significantly skewed blue values from low to high, with a minimum Delta E of 7.5 at 70 IRE and a maximum of 23.3 at 20 IRE. After calibration, the Delta E values in the Cinema mode were satisfactory, remaining below 3.3 at all levels except 20 IRE (5.6), 30 IRE (4.1), and 70 IRE (4.7). The TC-P50GT30’s pre-calibration THX color tracking (not shown) is significantly better than the Cinema mode’s out-of-box result. Both modes calibrate well, but as noted above, the Cinema mode was preferred because of its more appropriate gamma.
While the TC-P50GT30 is a good performer overall, it was outmatched by the VT30 and even by the ST30. For that reason, the TC-P50GT30 was not calibrated in 3D.—TJN