In this video, I'm going to do a professional, scientific review of the LG B7 TV, and I guarantee
you'll learn something you don't already know about the Korean brand's 2017 OLED televisions.
Keep watching.
Hello everyone, this is Vincent Teoh from HDTVTest here...
I'm a professional TV reviewer and calibrator.
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Let's get on with the review, starting with the design of the LG OLED55B7.
Because OLED TVs don't require a separate backlight unit, they can be made very slim,
and that's the case with the LG B7.
The black bezel is encased in a brushed silver metallic trim which extends around the back.
The bottom half of the rear chassis is finished in white, and becomes thicker to accommodate
the TV's processing, power circuit, connection ports and speakers.
To increase the picture immersion for users, LG has removed the logo that's normally
found on the bottom of the screen, and put it on the metallic crescent stand instead.
All the connections are located on the left side of the display, including four HDMI 2.0b
inputs with HDCP 2.2.
After setting up the LG OLED55B7V, we went straight into the service menu to find out
more details about the television.
As you can hopefully see for yourself, the B7 uses an inhouse M16P chipset which is the
same one found on the step-up E7 and W7... the company is telling the truth when it says
all of its 2017 OLEDs use the same SoC or System on Chip.
What this means is that even a £3000 B7 or C7 should deliver essentially identical picture
quality to the £8000 flagship W series, although there may be slight variation from one unit
to another.
But such variations will occur even within the same model range anyway.
Continuing our exploration of the service menu of the LG B7, we can see that the default
compensation cycle is exactly the same as that on 2016 models...
four hours of accumulated operation for a routine compensation cycle, and 2000
hours for a major one.
In case you're wondering, compensation cycles are implemented on OLED TVs to correct uniformity
issues, and are very effective in clearing up image retention.
If you've looked at my previous video where I was given 6 hours to test the E7 and W7
in San Francisco, you'll know that LG's 2017 OLEDs have cleaner and clearer above-black
handling than 2016 sets.
The LG OLED55B7 is no different.
When we watched a dark sequence in Skyfall towards the end of the movie where Javier
Bardem is approaching the chapel, the darker shades in the sky were noticeably less noisy
and pixellated than 2016 OLEDs.
If you've been troubled by excessive noise, macroblocking and pixellation in very dark
scenes especially when watching low bit-rate content on the 2016 LG OLEDs such as the B6,
C6 or E6, then you'll be pleased to know that this has improved a lot on the B7, C7, E7, G7 and
W7.
In my opinion, this is the single biggest reason that would tempt me to buy a 2017 LG
OLED over a 2016 one.
Near-black uniformity is very slightly improved over 2016 models.
On our B7 retail unit which was supplied by a shop, there's no vignetting whatsoever when
we put up 1% to 4% above-black full-field patterns to check in a pitch-black room.
Last year's LG B6 tend to exhibit some minor vignetting especially on the right side
of the screen.
However, there's little improvement in terms of thin streaks of vertical banding just above
black, although we rarely saw them in real-life viewing.
I'm not sure if you've spotted the blob surrounding the text at the bottom left of the screen,
but that's a mechanism to blunt the high-contrast, sharp edges on static logos and texts to combat
image retention.
Don't be alarmed if you see it on your TV... it's normal, it's been on the LG OLED TVs for as long as we
can remember, but perhaps more noticeable on 2017 models because of increased brightness.
Which brings us to the next area of improvement: bright scenes will generally look brighter
on the B7 compared with the B6, because LG engineers have reduced the ABL or Automatic
Brightness Limiter on their 2017 OLEDs.
Let me explain what ABL or Automatic Brightness Limiter is.
On self-emissive displays such as CRTs, plasmas and now OLEDs, a bright, full-screen image
will draw a lot of power, since every pixel has to be driven quite hard.
To control power consumption and to stop components from overheating, ABL is implemented to dim the
screen when how bright the overall picture is exceeds a certain threshold.
My esteemed colleague at HDTVTest, David Mackenzie, has authored an ABL test pattern which you
can see here being displayed on the LG B7.
The test pattern consists of an expanding black circle, then an expanding white circle.
As the amount of white increases on screen, you can actually see the exact moment the
ABL kicks in, the moment when the white dims down to become light grey.
Now here's the amazing thing about LG's 2017 OLED TVs including the OLED55B7.
the engineers have designed them such that if peak white was calibrated to 150 nits,
there is no ABL at all!
As you can clearly see here from the same test pattern.
Why is this important?
It's all to do with contrast which can be crudely defined as white divided by black,
and contrast is the number one determinant of picture quality according to the ISF or
Imaging Science Foundation.
Now, we all know that all OLED TVs are capable of 0 cd/m2 blacks, so the most straightforward
way to get a higher contrast is by brightening the picture.
To be fair, this increase in perceived contrast is not very visible in movies, which is why
many publications understate the importance of reduced ABL.
The Average Picture Level or APL in movies is usually below 10%, especially when the
top and bottom black bars are taken into account.
Even the brightest known title, The Art of Flight which is a documentary about snowboarding,
has only been calculated to have an APL of 32%.
Where the less aggressive ABL on the 2017 LG OLEDs will become noticeable is on computer
pages or bright splash screens, as you can see from the title menu of the excellent AVSHD
test disc displayed on a 2017 OLED beside a 2016 one.
Similarly, Apple adverts and ice hockey matches will look punchier, with the whites not turning grey.
Excessive adjustment of the [Colour Management System] or CMS can still introduce posterisation
artefacts, as you can see from this test pattern from the Spears and Munsil Blu-ray.
Luckily, on our retail sample which is NOT provided for review by LG, calibrating the
greyscale to an accurate level allowed the colours to fall into place quite nicely, so
we didn't need to touch the CMS at all.
When we watched some football in 1080i on the LG B7, we were surprised to see some repeatable
deinterlacing artefacts during slower passages of play, even with [TruMotion] disabled.
I've captured it on video, but due to compression it's going to be very difficult for you to
see in real time, so I'm going to slow down the relevant part.
Here's the first instance with [TruMotion] set to "Off", the ball is floating in the
air, wait for it, wait for it, boom, the ball splits into 3, with one artefact appearing
in front of the ball, and another appearing behind.
Next, let's check out the same footage with [TruMotion] off, and this time [Real Cinema]
off too.
Wait for it, wait for it, and bang.
The same deinterlacing artefact appears.
We troubleshooted with lots of different settings, and the only methods to eradicate the artefact
is by 1) by engaging [Game] mode.
Here's the footage - the ball is totally smooth as it travels through the air.
Also, if we send a 720p instead of 1080i signal, there's also no artefact, since the deinterlacing
is done by the set top box, not by the TV.
We think what's happening is that the LG B7 is confused by slower passages in play, and
misapplying film-mode deinterlacing when it shouldn't.
The easiest way to avoid such artefacts is by sending a progressive rather than interlaced
video signal to the TV.
On a 10% window and with white point calibrated to D65 industry standard, peak brightness
measured 750 nits in HDR mode on our LG OLED55B7V retail sample.
We know LG has been claiming 1000 nits at two or three percent window in HDR vivid mode,
but the highest we could measure from our 55-inch B7 was 880 nits even under these conditions.
Maybe 1000 nits is only achievable on 65-inch models, or on selected panels.
We'll see.
LG's tone-mapping algorithm for its 2017 OLED TVs including the B7 tries to retain as much
specular highlight detail as possible within the constraints of its 750-nit peak brightness,
so the overall image in HDR can look slightly darker, especially in 4K Blu-rays that are
mastered to 4000 nits.
We found it necessary to engage Active HDR - which is LG's technology to simulate dynamic
metadata from static metadata - to keep the picture bright enough.
Input lag measured 21 miliseconds in [Game] mode on the LG B7, but there's an even
better way to get the best of all worlds.
If you relabel the HDMI input as "PC", the input lag is also 21 miliseconds, and you
get the bonus of full 4:4:4 chroma, and you can still benefit from the accurate calibrated
colours in the [ISF Expert] modes.
Unfortunately this trick doesn't work in HDR - input lag was very high at around 104 miliseconds
even with the HDMI input relabelled to PC.
However, switching to HDR game mode dropped the input lag down to 21 miliseconds too,
and at least the [Colour Gamut] is not fixed to "Wide" so you can get more natural-looking
colours by switching it to "Auto".
A few other publications have concluded that the 2017 LG OLEDs offer only minor improvements
over the 2016 sets, and advise people to get the 2016 models mostly on the basis of value
for money.
I respectfully disagree, but that's because I'm a video enthusiast with a discerning pair
of eyes.
If you ask me to put an arbitrary percentage of improvement on the LG B7 over the B6, let's
see, cleaner near-black handling with clearer shadow detail, let's put it conservatively
at 10%; less ABL for a brighter picture with higher perceived contrast, 5%; slightly better
upscaling, 3%; lower input lag with the potential for accurate colours and full 4:4:4 chroma
in SDR, 5%; the availability of two-point [White Balance] controls for more accurate
HDR colours, 5%; better HDR tone-mapping, another 5%; improved anti-reflective filter that no
longer suffers from a magenta tint when hit by light, 2%.
When you add all these together, we're talking about a 35% improvement over 2016
sets - of course it's just a random number I plucked out of the air, but don't let anyone
tell you the improvements are minor.
The Panasonic and Sony OLED TVs may beat the LG at certain things, but it will be extremely
close, and they are going to be more expensive.
The B7, any 2017 LG OLED in fact, will end up being one of the best TVs you can buy this
year.
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