Panasonic TH-50PZ80U Plasma TV review: input lag, deinterlacing, and upscaling for retro gaming (480i)

This 1080p Plasma TV from 2008 is very unique and quite nice in many ways. It used to retail for around $2000. If you can find one it's a great choice for retro gaming. 

Overview/Image quality

This is a plasma TV, which generally means at least the following: nearly infinite viewing angles, and jaw dropping weight. That's true in this case as well. This 50" model weights 85lbs. 

At native resolution (1080p) this TV can be set to zero cropping, and in that mode is pixel perfect, with zero aliasing.  480p/i crops 25 pixels off the side and 15 off the top/bottom; as far as I could tell there was no way to reduce this, and furthermore it was forced 16:9 aspect ratio. If you have the remote it's probably possible to get 4:3, but this isn't exposed in the menus you can get to without the remote.



480p/i looks pretty good, with only a little aliasing or jagged edges. It's much improved relative to the upscaling on the native 720p Panasonic sets from the same era.

720p crops even more, 35 pixels from the sides and  20 off the top/bottom, and has somewhat worse aliasing and jagged edges than 480i/p.

It has all the standard inputs, including 3 HDMI, VGA, and 2 yPbPr.

One thing that's a little odd is that there seems to be some kind of defect on the inside of the glass, which I have now seen in three Panasonic plasma TVs. It's kind of like a sputtering of very dilute yellow paint - I assume this defect develops with age. So be sure to check your second hand set before spending money on it.

Measuring Input Lag

This display does not have a game mode; just a game 'color' preset that has no effect on lag. I tested all quality settings; none changed the lag. 

I used a piLagTesterPRO to measure input lag. This device sends a frame of video over HDMI and measures how long it takes to display it. I measure at the top and bottom of the screen, but as it turns out these produce the same results: the entire frame updates at the same moment, top to bottom. I've seen at least one other plasma display that drew the screen faster than the refresh rate but this is the only model that does the entire thing simultaneously. 

Full Input Lag Results 

I report two kinds of values. 1st response measures how long it takes for the TV to start responding (I use a 5% change in display brightness). This overly optimistic value doesn't tell how long it takes to see anything useful, but matches what other reviewers call input lag. full response is a more realistic measure of lag, and requires the display to reach 80% of full brightness. This combines both input lag and response time, and is closer to what you would actually experience in a game.

Normally I have an entire table of results here, but they'd all be exactly the same. This TV updates every pixel simultaneously, top, bottom, and middle.  It starts to update those elements 28ms after a frame is sent to the set, and finishes around 6ms later, at about 34ms. So instead of a table, let's look at exactly what happens to the brightness over time. This graph is actually from a different Panasonic plasma that I tested before, but this TV performs exactly the same (all the Panasonic plasmas I've tested perform identically, despite the wide range of model numbers).


This TV, unlike a LCD, flashes all pixels briefly a couple times and then goes dark between frames. This means the viewing experience is a bit more like watching a CRT. This is good for reducing motion blur, although the display is not without motion artifacts. It's a little unclear where the fair point to measure input lag is, since the display starts to flicker very dimly for ~5ms before abruptly jumping to half and then full brightness. I kept my regular 5% threshold which makes the input lag appear extra low and conversely the response time somewhat longer. The full response (or realistic lag) may be the fairest way to compare this set to others.

Interestingly, all resolutions have the same timing. That's true even for interlaced content. Hold on, how can that be? Fair question. The set adaptively switches between bob and weave deinterlacing depending on much motion there is. Truly impressive stuff. This algorithm is as fast as possible, but blocky, on high-motion stimuli, and sharp and crisp for static stimuli. The tradeoff is that for high motion stimuli it is fairly blocky looking compared to what good traditional deinterlacer would produce (such as on Sony sets).  Given the choice for action games I think I like using my OSSC to deinterlace with 25% alternating scanlines, as this cuts the blockiness some, but the built in deinterlacing is great and would be ideal for RPG style games. 

Results compared to other displays

To allow quick comparison between many displays I've summarized the results across all the displays I've personally tested with the piLagTester Pro. Min lag is the first response at the top of the screen, real lag is the full response at the bottom. The min lag value is really unfair to this set, so I've written it out in green. I'm sorting here by 480i since that's where this TV is truly untouchable.

DisplayYear made (TV?)Native Resnative min lagnative real lag480i real lag480p real lag720p real lag1080p real lagnative response timenative scan out
Panasonic TH-58PE75U2008720p28.034.034.034.034.034.06.000.00
Panasonic TH-42PX75U2008720p28.034.034.034.034.034.06.000.00
Panasonic TH-50PZ80U2008720p28.034.034.034.034.034.06.000.00
Dell E2211H20141080p3.033.634.734.534.133.815.0015.57
Corprit D157 (hdmi)20211080p3.134.534.934.834.633.916.2515.13
AOC/Envision G19LWK2010900p3.131.239.538.738.437.815.5012.60
sony XBR 43X800D20174k24.544.346.546.044.644.75.0014.83
LG 42LC2D2006720p28.350.654.650.850.46.3015.95
Samsung LN32D4032012720p20.941.258.942.440.740.75.5014.83
TCL 40S32520211080p6.527.360.629.027.927.76.0014.83
Vizio E261VA2012720p19.359.061.160.459.258.925.0014.67
Samsung P2570HD20101080p37.062.062.062.062.062.010.0015.00
Samsung LN32B3602010720p37.660.062.161.860.560.18.0014.40
Dell U2410 (game)20101080p4.026.262.228.326.526.56.0016.20
Dell U2410 (sRGB)20101080p20.542.862.445.043.143.16.1316.13
ACER AT326520121080p19.543.862.745.343.843.88.0016.27
RCA L40FHD4120101080p20.346.665.048.047.046.09.6816.63
Sony 40VL130 (game)20081080p22.847.366.349.047.347.39.0815.43
Sony KDL-40V300020081080p22.250.168.450.650.549.811.0016.93
Toshiba 40L2200U20141080p30.056.074.056.056.056.010.0016.00
TCL50s42320214k14.042.075.042.042.042.013.0015.00
Mitsubishi LT-4614420081080p51.068.075.068.068.068.09.008.00
TCL 49s40320184k6.130.276.830.930.330.78.0016.13
Polaroid FLM-373B2007720p28.049.082.049.049.049.07.0014.00
Samsung LN46B61020121080p53.066.082.066.066.066.05.008.00
Vizio VO370M20101080p2.523.683.049.047.024.35.4715.67
Sharp LC-C3234U2009720p33.064.683.666.664.615.0016.60
Philips 42PFL3603D/F720091080p29.050.084.050.050.050.05.0016.00
LG 42PT35020121080p63.567.785.968.967.767.74.200.00
Sony KDL-46EX40020101080p28.052.087.052.052.052.08.0016.00
Vizio xvt4735v20111080p67.688.688.889.288.688.69.0012.00
Toshiba 46L5200U20131080p55.071.089.076.071.074.08.008.00
Sony 40S20L12007720p48.472.090.172.973.49.6014.00
Samsung LN46C63020121080p54.572.190.790.388.572.310.007.63
Vizio VO22L FHDTV10A2008720p28.061.094.061.061.061.018.0015.00
Samsung HP-T425420111080p69.775.794.176.075.75.001.00
Vizio E261VA2007720p28.062.095.062.062.062.018.0016.00
GPX TDE3245W2016720p28.051.0102.051.051.051.08.0015.00
SANYO DP507492010720p67.075.0103.094.079.075.07.001.00
Emprex HD 32022007720p27.057.1126.051.050.026.515.1315.00
Vizio E470VL (hdmi)20111080p69.086.0128.095.095.086.09.008.00
LG 47LW6500-UA20121080p66.680.7149.7149.081.780.92.2711.83

The only other TV that comes close is a recent Sony 4k TV (sony XBR 43X800D) that does bob deinterlacing, not adaptive deinterlacing like this set. And that Sony is still 12ms slower, almost a full frame. 

This TV even compares favorably to a CRT. A CRT takes 16ms to draw from the top to the bottom of the screen. Some people consider counting this refresh time as unfair, but keep in mind that consoles update the screen between frames not during them so the game state is definitely 16ms stale at the bottom of the screen when refreshing at 60hz.  From this perspective, this TV is only 16ms slower than a CRT. I don't consider 16ms of extra lag to be an issue. The only remaining reason to choose a CRT over this set is that CRTs have no aliasing issues or upscaling problems for 480i/p. That's not a small thing, but if you can't have both in your home, this seems like a winner. If you can find it.

It's also one of the lowest lag TVs as measured by "real lag" at native resolution (that is, factoring in response time and scan out time), with only 3 TVs beating it. Of course, desktop monitors are faster, so if you don't need the display size of a TV that's a much more viable option. Of course, those PC monitors won't deal with 480i very well or at all. 

Conclusion

This is an old set, long since discontinued. But in a big metro area it's not hard to find one for sale or even given away for free (that's my source). 

If you have the space for it, it's always better to have a CRT for the retro gaming, along with a nice 1080p/4k flat screen for modern gaming. But if you can't fit all of those in your space, this is a great choice. Good retro; good modern.

BUT: Make sure to get a remote. It's not really possible to operate without one. 
 

Other models  

I tested the 50PZ80U  here, which shares the same manual with the TH-42PZ80U and TH-46PZ80U.  I've also personally tested the TH-42PX75U and the TH-58PE75U in other reviews on this site and they perform the same as this model. Panasonic's model numbers are hard to follow, so I can't be sure, but the motherboards of the TH-50PX75U, TH-42PX77U, TH-42PC77U, and TH-42PX75U look identical to the 42PX75U  so I'd suspect they would perform similarly. I'd suspect any Panasonic ending in 80U would also perform the same as this set in terms of lag. But in terms of upscaling 480i/p, the 1080p sets are way better than the 720p sets. 


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