Dark scenes / shadow issue on 4k TV

Phonesis · 29 Jul 2016 at 09:53

I recently got a 50" Panasonic 4k TV. It's a mid range one but am pretty impressed with picture etc.

However, I'm noticing a sort of polarisation or flickering effect with certain shades of shadow / black in some content. It's mostly stuff that's either SD or 720p HD and compressed (Sky HD content).

It's like the shadows are sort of dancing / flickering as opposed to being a true uniform shade of black or grey. In 4K content I'm not noticing it but only really seen a couple of shows on Netflix so far.

I never noticed this with my old 1080p HD set. Is it common with 4K TVs trying to display sub 4K content? I'm guessing the resolution of the screen exposes compression more and shadows tend to take a big hit from that. Seems to expose something I didn't notice coming from a HD TV.

nightrider1470 · 29 Jul 2016 at 10:40

Are you connected via Ethernet cable for Netflix? Blacks don't look great on Netflix as it's been downgraded from its source

Phonesis · 29 Jul 2016 at 11:41

nightrider1470 said:
Are you connected via Ethernet cable for Netflix? Blacks don't look great on Netflix as it's been downgraded from its source

I stream Netflix over WiFi. But it seems ok though. Issue is more with Sky HD content I think.

BassPunk · 29 Jul 2016 at 23:44

Turn the brightness down until they disappear.

mr griffin · 1 Aug 2016 at 21:27

I hope it's not for your sake, but it could be "posterization"

I had 3 Samsung led TV's all of them suffered from posterization so much so that I couldn't stand watching it as I would just notice it all the time on lighter blacks especially.

I sent all 3 tv sets back and even got a Samsung engineer out - who said to me it was a screen lottery depending on where they were made.

In the end I bought a Panasonic vt50b plasma and all was good in the world again lol.

I am looking forward to moving to 4k as soon as they start broadcasting most HD channels in 4k, then I'll have all the fun again.

Phonesis · 10 Aug 2016 at 10:27

mr griffin said:
I hope it's not for your sake, but it could be "posterization"

I had 3 Samsung led TV's all of them suffered from posterization so much so that I couldn't stand watching it as I would just notice it all the time on lighter blacks especially.

I sent all 3 tv sets back and even got a Samsung engineer out - who said to me it was a screen lottery depending on where they were made.

In the end I bought a Panasonic vt50b plasma and all was good in the world again lol.

I am looking forward to moving to 4k as soon as they start broadcasting most HD channels in 4k, then I'll have all the fun again.

Just seen this.

So after lots of fiddling about with settings it turned out to be a contrast issue. For really good quality content (1080p, 4k) the contrast setting everyone seems to recommend for this TV is basically fine (around the 90 mark) but it's too high for lower quality stuff and it causes problems I found.

For poor quality, compressed video you really start seeing horrible artefacts in shadow. Looks like a bit of shadow stuttering, polarised shades of grey, halos etc. I knocked the contrast down to 65 and about 90% of all that suddenly vanishes. With gamma at 2.3 and the backlight at about 80 or so (I like it bright) it is pretty much fine with all content.

So I think it was really a case of me blindly going along with recommended settings. Different content / room conditions are a factor. Pretty happy with the picture now. May drop backlight down again but will play with it.

My only real grip with the TV now is that Game Mode is hidden in a sub menu, meaning you have to navigate to it each time to turn off/on. Wish there was "Game Mode" button on remote. But minor.

For the money, and it's ultimately an entry level 4k/HDR TV, I am pretty happy now.

So for anyone else with the issue, I recommend the AV Forums True Cinema picture settings but with:

Contrast: 65 (or that area)
Gamma: 2.3 (that is recommended anyway)
Backlight: imo maybe higher than 47 - but I like it bright.
Adaptive Backlight: Definitely keep on min or off (min probably best).

Edit: for reference, the TV in question is a DX700b (50 inch).

jpaul · 10 Aug 2016 at 12:22

If you can find them 10 point 'advanced' gamma and white balance settings which seem also to be an option on dx700 (I have an older et) may be revelatory.
I do not understand why reviews do not post them much (job preservation independent calibrators)
so something that looks like this (the gamma stuff is making the low intensity levels brighter than they would be by default)
( Is there a big database of these I have never stumbled across )

W/B Adjustment
W/B High Red 3
W/B High Green 0
W/B High Blue 2
W/B Low Red -4
W/B Low Green 0
W/B Low Blue -1

More Detail Adjustment
IRE Red Green Blue
10 8 0 -50
20 0 0 -8
30 0 0 0
40 0 0 0
50 0 0 0
60 -10 0 0
70 -7 0 15
80 0 0 0
90 21 0 0
100 -50 17 -37

Gamma (Target 2.2)
IRE Gain
10 6
20 43
30 49
40 50
50 50
60 30
70 34
80 -1
90 5
100 0

Phonesis · 10 Aug 2016 at 13:06

jpaul said:
If you can find them 10 point 'advanced' gamma and white balance settings which seem also to be an option on dx700 (I have an older et) may be revelatory.
I do not understand why reviews do not post them much (job preservation independent calibrators)
so something that looks like this (the gamma stuff is making the low intensity levels brighter than they would be by default)
( Is there a big database of these I have never stumbled across )

Thanks for these. I did see the 10 point option in the settings for the TV and AV Forums did cover it in a video actually. Just not sure it's quite right (they didn't factor in SD content maybe). Will give yours a go.