Note: Our Panasonic TX-P65VT30B review sample was calibrated using Calman Professional, the industry-leading video calibration software.
2D Mode Greyscale
|Pre-calibration RGB tracking and delta errors (dEs)|
Remembering that the [THX] picture mode is designed to be the next best thing to an individually calibrated HDTV, we allowed our TX-P65VT30 review sample to warm up, then measured some Greyscale test patterns to see how well it was doing.
THX and Panasonic might want to investigate this, because there’s a not devastating, but also not unsubtle green cast to the TX-P65VT30′s images prior to calibration. This has been the case on many of the Panasonic Plasma TVs that we (as well as other review outlets) have measured this year, suggesting that it affects more than one batch of panels. This does give a slight green haze to images, although readers should remember that since we’re used to looking at calibrated HDTVs as the rule rather than the exception, we’re likely to be more sensitive than most to these sort of inaccuracies.
|Post-calibration RGB tracking and dEs in [Professional] mode|
We then calibrated the Panasonic TX-P65VT30B, firstly by adjusting the two-point White Balance control, as directed by the measurements from our calibration meter and CalMan software. The two-point control allows for the Greyscale mixing to be adjusted in the darker and the brighter shades, respectively. This process mostly involved reducing the [G-Gain] control by a fairly hefty amount, and then making small corrections to red and green as appropriate. This left us with highly accurate picture quality, although we had a subtle excess of blue left over in shadowed areas. Since we had access to full 10-point precision controls, we then made further adjustments on top of the 2-point adjustments. The result, unsurprisingly, is Grey shades that contain a visibly perfect mix of Red, Green and Blue at all brightness levels.
Of course, as we’re used to seeing from consumer-grade Plasmas, the Greyscale mixing varies depending on the APL – that’s the Average Picture Level, or average brightness of a scene. To give readers an idea, we achieved the above, perfectly accurate result using the specialised APL test patterns on the AVSHD calibration disc. The APL pattern contains all of the different brightness levels on screen at the same time, only swapping the middle one out so it can be read by the calibration meter, rather than showing one brightness level at a time. This means that during our calibration process, the Plasma TV was using the same driving mode. By contrast, we’ve found that when using the windowed measurements, the VT30 will make small adjustments, particularly when we display the darkest and brightest test cards. After calibrating with the APL patterns, we then ran a new series of measurements using windowed greyscale patches, and sure enough, the measurements were different, being slightly more blue – although not horribly so (there was roughly a 5% excess of the colour). The area of Greyscale consistency is one where LCD TV displays are ahead of Plasma, although the flaw is subtle – and LCDs typically suffer from the worse problem where greyscale mixing changes depending on the viewer’s seating position.
|Gamma curve in [Professional] mode||Corresponding gamma tracking|
Gamma tracking, which describes the amount of light being displayed on the TV screen relative to the amount of light specified in the video signal, is fairly unpredictable on Panasonic’s consumer PDPs (plasma display panels). For example, most of the ones we’ve reviewed this year have “risen out of black” too quickly, or in other words, although they have a very deep shade of absolute black, they tend to over-emphasise darker parts of the picture. It’s a fairly subtle inaccuracy though, and we don’t recall reading any complaints over it. Again, the results vary depending on whether windowed, or APL test patterns, are used to gather measurements. We used the APL patterns to calibrate, because these arguably correspond more to actual video content than the windowed patterns do (although we welcome debate on the subject). Unsurprisingly, since the TX-P65VT30 features a 10-point gamma control, we were able to achieve a measurably perfect result. With real-world footage, we couldn’t spot any problems, and images appeared with a good amount of realism and depth (which bad Gamma tracking tends to harm).
One problem we ran into later, though, was the infamous floating gamma issue that we spotted during our first assessment of the 2011 Panasonic Plasmas. For the uninitiated, this issue basically meant that the overall brightness of dark scenes would, fairly rarely, jump up about a second after a scene change. Fortunately, we did manage to get float-free viewing, but calibrators have to be very careful with the 10-point Gamma control to avoid reintroducing it. We’ll explain more in the “Black Level” section of this review.
2D Mode Colour
Panasonic Plasmas haven’t had any significant colour inaccuracies for a few years now, and the TX-P65VT30B is no different. Other than a red which was tilted slightly towards orange, and an oversaturated green, measured errors were low, translating into very naturally coloured images.
Of course, with the amount of calibration controls present on TX-P65VT30, and Panasonic’s history of implementing these correctly, we had no problem achieving perfection in all three colour areas – hue, saturation…
|Post-calibration CIE chart with reference to HD Rec.709|
|Post-calibration colour luminance (coloured bars = targets; black bars = measured values)|
During the 3D calibration process, we attached the active-shutter 3D glasses to the front of our Klein K-10 calibration meter, meaning that we could adjust the picture settings to take the darkening and tinting effects of the 3D eyewear into account.
3D Mode Greyscale
|3D Pre-calibration RGB tracking and delta errors (dEs)|
We grabbed one of the pairs of active-shutter glasses that Panasonic supplied with the TX-P65VT30, attached them to our meter, and ran the same measurements again, this time with the plasma panel outputting in 3D display mode.
The Panasonic TX-P65VT30B displayed a less accurate out-of-the-box 3D image than the smaller 50″ version did, although we noted that one of the same errors was present: blue-tinted shadow areas. On the 65″ model we reviewed here, brighter areas were tinged slightly green, just like the 2D mode. We should point out that in 3D display technology – especially in the active shutter system – the individual glasses often have their own distinct colour cast (sometimes it even varies between the left and the right eye areas).
|3D Post-calibration RGB tracking and dEs in [Professional] mode|
Few home users will have access to the meters necessary to calibrate in 3D, but since we do, we saw how far we could push the Panasonic TX-P65VT30. Again, we had no problem achieving flat greyscale tracking due to the 10-point White Balance control, which is present even in the 3D mode. This definitely improved neutrality with 3D content, and flicking back and forth between 3D and 2D display modes (and of course flicking the glasses out of our eye-line) revealed very little in the way of tints. (It did remind us just how much darker the 3D images are, of course).
3D Mode Colour
Surprisingly, the entire colour gamut in 3D mode was constrained when using the factory settings on the TX-P65VT30B. Red, green and blue were desaturated, when compared to the Rec.709 HDTV standard (which appears to be the de facto standard for extra-dimensional content, too). This left us worried, because when we see colour saturation limitations in a default mode, it’s often because the panel isn’t capable of any more. Fortunately, this wasn’t the case with the 65VT30 – we were able to bring all of the primary and secondary colours into spec using the [Colour Management] menus, with the exception of blue, which we weren’t able to fully saturate through the 3D glasses.
|3D Post-calibration CIE chart with reference to HD Rec.709|
|3D Post-calibration colour luminance (coloured bars = targets; black bars = measured values)|
Benchmark Test Results
|Screen uniformity||Near perfect, full white screen reveals tiny discrepancy towards right of screen|
|Overscanning on HDMI||0% with [16:9 Overscan] disabled|
|Blacker than black||Passed|
|Calibrated black level (black screen)||0.011 cd/m2|
|Calibrated black level (ANSI checkerboard)||0.013 cd/m2|
|Black level retention||Floating gamma if 10-point Gamma control used to extremes, see “Black Level”|
|Video mode deinterlacing||Very effective jaggies reduction|
|Film mode deinterlacing||Passed 2-2 PAL film test, but may be intermittent|
|Viewing angle||Perfect horizontally; screen filter lessens vertical viewing angle|
|Digital noise reduction||Present, optional, not forced|
|Sharpness||Defeatable edge enhancement|
|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||23ms compared to lag-free CRT|
|Full 4:4:4 reproduction (PC)||No, colours slightly blurred|
|Default [Normal] mode (2D)||244 watts|
|Default [Normal] mode (3D)||289 watts|
|Calibrated [Professional] mode (2D)||253 watts|
|Calibrated [Professional] mode (3D)||307 watts|
Measurements taken with full 50% grey screen.
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