About OLED colour accuracy in HDR mode: LG vs Sony - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 17 Old 10-02-2018, 01:31 PM - Thread Starter
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About OLED colour accuracy in HDR mode: LG vs Sony

Hi everyone... I am a pro calibrator from Brazil, long time lurker here. One hot topic here is always wich oled to get: Sony or LG.

Well... I had both and made a long term testing and analysis on an A8F and on a B7P. After some time testing both and making measures i can say one thing: If color accuracy matters to you, dont buy an LG. I simply cannot understand why HDTVTest, Rtings and others doesn't say anything about this...

The fact is that the trick that LG uses to get higher peak brightness than the other brands using the same panel involves pushing the white subpixel too far. The white subpixel on WRGB oleds is the biggest and capable of pushing higher brightness. The aproach that LG uses is push it as hard as it can and just ignore the fact that the other subpixels cannot follow it. With this aproach you get brighter highlights but a narrower color volume on the top end.

Here are measuraments i took from the DCI P3 colour space from both TVs. Sony on top, LG on bottom.


As you can see, from a first look it seems that the LG get the saturation points slightly better than the Sony right?
Now let's get to the hard numbers... Here are the saturation points from red, but all the other colors show similar results.
Again, Sony on top, LG on bottom.



Delta error of 1-2% on the sony on all saturation points and as high as 12% on the LG! That's because the issue is not the XY delta, but the color brightness! On the LG the 100% red is 43% darker than it should be.

How that translates in the real world? with the white subpixel making the colors lose their depth and looking brighter and less saturated..

I tried to take some photos... they give some ideia.

Sony A8F:


LG B7P:


This is the "magic" that LG uses to get their high peak brightness, and it does more harm than good.

Another point that the reviews forget to say: On LGs game mode you cannot even get 6500k colour temp because all you get is an warm/cold slider. So, the input lag is indeed slightly lower, but forget about any kind of color accuracy in your games.

So... It's not just about "buy the cheaper one", if color accuracy matters, the difference is huge in HDR.

Last edited by henrique33; 10-02-2018 at 01:53 PM.
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post #2 of 17 Old 10-02-2018, 01:39 PM - Thread Starter
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Oh... and it seems that on the C8 The LG make this even worse to get the 800+ peak brightness. Here are some measurements from Rtings

Again, look at the DeltaE tab, below 2% on the Sony, and way higher on the C8.
How come no one says anything about this?

Sony A8F:


LG C8:
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post #3 of 17 Old 10-02-2018, 09:25 PM
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Quote:
Originally Posted by henrique33 View Post
Another point that the reviews forget to say: On LGs game mode you cannot even get 6500k colour temp because all you get is an warm/cold slider. So, the input lag is indeed slightly lower, but forget about any kind of color accuracy in your games.
The C8 supports LUT calibration for both SDR and HDR Game Modes, so you can get an accurate image for games without extra lag.
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Chris Heinonen
Staff Writer, The Wirecutter, a NY Times Company
Founder/Editor, ReferenceHomeTheater.com
ISF Level II Certified Calibrator
Previously: Secrets of Home Theater and High Fidelity, AnandTech.com, HDGuru.com and Electronic House
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post #4 of 17 Old 10-03-2018, 07:02 AM
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It looks like the LG drives the white subpixel a little harder than the Sony.
Is there no way to correct for these errors and get a better cal?
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post #5 of 17 Old 10-03-2018, 07:21 AM - Thread Starter
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Originally Posted by Smackrabbit View Post
The C8 supports LUT calibration for both SDR and HDR Game Modes, so you can get an accurate image for games without extra lag.
Never used it. Works well on the C8?
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post #6 of 17 Old 10-03-2018, 07:22 AM - Thread Starter
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Originally Posted by obveron View Post
It looks like the LG drives the white subpixel a little harder than the Sony.
Is there no way to correct for these errors and get a better cal?
No. If you use the CMS in HDR you get nasty artifacts. If you dial up the color control you get more luminance, but oversaturated tones.
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post #7 of 17 Old 10-03-2018, 07:40 AM
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Originally Posted by henrique33 View Post
Never used it. Works well on the C8?

Just ask @sillysally

He recently purchased a 77" C8

There is no perfect display, quit looking for faults and enjoy

LG OLED 65” B7 and 55” C8
Ascend's with RAAL, Love my PSA v1800 and a 7.2.4 speaker config, Oppo 203 and other stuff
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post #8 of 17 Old 10-03-2018, 09:16 AM
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Color luminance will be very low, especially for red and yellow - if you don't enable dynamic tonemapping or force static metadata for peak luminance in the 501-511nits range. If you have an hdfury vertex or linker device you can push the metadata string of 501 nits for the highest color volume, often exceeding the dynamic tonemapping color volume.

This puts the display in a near reference mode, clipping detail above 1000nits. Just keep in mind that any films mastered up to 10,000 nits and have high apl will exhibit lots of clipping.
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post #9 of 17 Old 10-03-2018, 10:26 AM
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Funny enough I got the A1e earlier this year and the peak highlights didn't have the pop I was looking for so I got a LG C8 recently which was definitely brighter but colors on HDR seemed less saturated. This was most noticeable to me on Spiderman on PS4 Pro. Flipping between the two, the Sony colors seems more aesthetic and fuller. I still prefer the LG tone-mapping for most HDR content because of how highlights pop but the color saturation differences made me decide to keep the A1e and return the c8. The difference in highlights was minimal in the content I normally use (AAA games and HDR netflix) and because all the games I play are 4K-HDR the lag is almost identical (~29-30ms for both sets).


This Rtings image sort of illustrates the difference in color that I saw. (C8 on the left, A1e on the right)



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Game Room: Sony 65" A1E | Denon AVR-S710W | LR: Chane 5.4 | C: 2.4 | SR/SL: Polk OWM3 | HL/HR: Micca Covo-S | Sub: SVS SB-12
Bedroom: Samsung 40MU7000 | Schiit Fulla 2 | Adam Audio T5V

Last edited by mosiris; 10-03-2018 at 10:30 AM.
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post #10 of 17 Old 10-03-2018, 11:30 AM - Thread Starter
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Quote:
Originally Posted by amdfanTO View Post
Color luminance will be very low, especially for red and yellow - if you don't enable dynamic tonemapping or force static metadata for peak luminance in the 501-511nits range. If you have an hdfury vertex or linker device you can push the metadata string of 501 nits for the highest color volume, often exceeding the dynamic tonemapping color volume.

This puts the display in a near reference mode, clipping detail above 1000nits. Just keep in mind that any films mastered up to 10,000 nits and have high apl will exhibit lots of clipping.
This was measured with 1000 nit static metadata and was observed with dynamic tone mapping on and off. On the Sony it never happens.
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post #11 of 17 Old 10-03-2018, 11:36 AM - Thread Starter
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Exactly what i am saying, peak brightness at the expense of colors not worth it IMO
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Originally Posted by mosiris View Post
Funny enough I got the A1e earlier this year and the peak highlights didn't have the pop I was looking for so I got a LG C8 recently which was definitely brighter but colors on HDR seemed less saturated. This was most noticeable to me on Spiderman on PS4 Pro. Flipping between the two, the Sony colors seems more aesthetic and fuller. I still prefer the LG tone-mapping for most HDR content because of how highlights pop but the color saturation differences made me decide to keep the A1e and return the c8. The difference in highlights was minimal in the content I normally use (AAA games and HDR netflix) and because all the games I play are 4K-HDR the lag is almost identical (~29-30ms for both sets).


This Rtings image sort of illustrates the difference in color that I saw. (C8 on the left, A1e on the right)