We can remember about 10 years ago when 17" and
19" screens ruled the desktop monitor market. Something like the 24" Dell
2405FPW seemed a massive screen at the time and it was hard to imagine anything
bigger on your desk. Flash forward to the end of 2014 and we have something
rivalling many peoples TV's on our work-bench, a massive 40" display from
Philips. The BDM4065UC is officially a desktop monitor in Philips' range, not
only offering a huge screen size but also quad HD "4k" support. The 3840 x 2160
resolution is ideal for a screen this size for both desktop and multimedia use.
The BDM4065UC comes with a pretty impressive spec and feature set and all at a
very reasonable price. We will put it through its paces during this review.
Commenting on
the new 40-inch display with UltraClear 4K UHD resolution, Thomas Schade, Vice
President EMEA at MMD says, �This new UltraClear UHD display is an exciting
addition to the 4K line-up and sizes up the viewing experience at 4K level. With
the clarity and brilliance of 4K UHD and 40 inches of screen real estate to play
with, users will really notice the sense of space and precision detail in
everything they do � from complex financial applications and scientific imaging
to gaming or streaming movies.�
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The Philips BDM4065UC offers a good range of
connectivity options with D-sub, HDMI, Mini DisplayPort, DisplayPort, MHL-HDMI
and RS232 all provided. This should be enough for a wide variety of systems and
external devices. Philips' "MultiView" function allows for multiple inputs to be
shown on the screen at the same time, up to 4 simultaneously in fact. This is
basically a Picture in Picture (PiP) or Picture By Picture (PbP) function, and
because of the massive 3840 x 2160 resolution, you can actually have four 1920 x
1080 showing on the screen at the same time if you want! There's a wide range of
configuration options detailed in the user manual for the MultiView settings.
The screen has an integrated power supply and so
it only needs a standard kettle lead which is provided in the box. There is a
built-in 4 port USB 3.0 hub as well on this model, one with fast charging
capability. The ports are the latest USB 3.0 generation
which is good and located separately on the back of the screen. There are also a
few other extras including integrated 2x 7W stereo speakers, an audio input
connection and headphone jack.
Below is a summary of the features and connections
of the screen:
Feature
Yes / No
Feature
Yes / No
Tilt adjust
DVI
Height adjust
HDMI
Swivel adjust
D-sub
Rotate adjust
DisplayPort
VESA compliant
Component
USB 2.0 Ports
Composite
USB 3.0 Ports
Audio connection
Card Reader
HDCP Support
Ambient Light Sensor
MHL Support
Human Motion Sensor
Integrated Speakers
Touch Screen
PiP / PbP
Hardware calibration
Blur Reduction Mode
Uniformity correction
G-Sync
Design and Ergonomics
Above: front views of the screen. Click for larger versions
The BDM4065UC has an attractive design, with
subtle thin bezels and a minimalist stand. The bezel is a glossy black
plastic measuring ~12mm around all sides of the screen. In the middle of
the bottom bezel is a protruding black plastic section with a Philips logo
and power LED on it. The LED glows white during screen operation. There
are no other markings or model designations on the front of the screen at all.
Above: rear
view of the screen. Click for larger version
The back of the screen is a squared off matte
black plastic which nicely encloses all the innards. There is a power
socket on the left hand side (as viewed from behind as above). On the right
you will notice the USB ports as well. The video connections are located
on the right hand edge of the central back section which we will show you
in a moment. There are VESA 200mm mounting holes provided on the back as
well. The stand is packages separately and must be screwed onto the small
metal arm provided, and slotted into the bottom of the
screen where it is attached using the 4 provided screws.
Above: view
of the stand. Click for larger version
The base is a minimalist aluminium stand as shown
above. It gives the screen a sturdy base and looks like a lot of current
TV stands you will see.
Above:
further views of the stand and base. Click for larger versions
Above you can see the stand from some other
angles, including on the right where it slots into the bottom of the
screen on the back. The bottom edge of the screen is ~73mm from the edge
of the desk.
Above: side
view. Click for larger version
The display has a fairly thin side profile so
would be nice wall mounted. One main downside to this screen is the lack
of any ergonomic adjustments at all. The screen sites up vertically as you
would see from TV's. If you're sitting a couple of metres away for a game
or movie this should be fine and what you want. However, if you're sitting
a few feet away from a normal everyday desktop position, the lack of tilt
is annoying. We ended up propping a small book underneath the front of the
base to tilt it back slightly to write this review. There's no tilt,
height, swivel or rotate adjustments at all from this screen so be wary.
Mounting the screen on a monitor arm would give you more flexibility but
obviously add to the overall cost. The stand is like most TV designs which is
one thing, but this is supposed to be a desktop display so we would have
liked more from the stand on this screen.
A summary of the screens ergonomic adjustments
is shown below:
Function
Range
Smoothness
Ease of Use
Tilt
None
n/a
n/a
Height
None
n/a
n/a
Swivel
None
n/a
n/a
Rotate
None
n/a
n/a
Overall
Lack of any ergonomic adjustments which is a
shame
The materials were of a good standard and the
build quality felt good as well. There was no audible noise from the screen,
even when conducting specific tests which can often identify buzzing issues.
The whole screen remained reasonably cool even during prolonged use as well,
with a bit of heat given off.
Above: interface connections on right hand side back of the screen
Above: USB interfaces back of the
screen. Click for larger version
The right hand side of the back central section
features all the video connections as shown above. There are also the audio
connections here, all pretty easy to get to and access if you need to. On the
back of the screen are the 4 USB 3.0 ports (and 1x upstream) which are again
easy to access.
OSD Menu
Above: views of
OSD operational buttons on the bottom right hand edge of the screen
The OSD menu is controlled through a single
joystick controller which is located on the back right hand corner of the screen
(as viewed from the front). This controls all aspects of the OSD and does take a
bit of getting used to. The menu software is pretty big and looks low-res on
such a nice high res screen. It serves its purpose though.
The joystick gives you quick access to a few
options. Pressing it left brings up the SmartImage preset mode menu as shown
above.
Pressing the joystick up brings up the MultiView
menu, and down brings up the audio source menu.
Pressing the joystick right brings up the main OSD
menu as shown above. It's split in to 8 sections shown down the left hand side,
with the relevant options for each section shown on the right hand side.
You have to press the joystick left to go
back/exit a menu. Pressing the joystick in like a button actually doesn't do
anything, contrary to what you might expect. Once you're in a menu it's a bit
tricky at first to figure out what does what. Sometimes you need to press right
to go into a section, then when you're in the option (like brightness for
instance) it brings up a separate control for the brightness setting, at which
point rather than using left and right to slide the setting left and right as
you would expect, you revert to using up/down to change it. It can be a bit
confusing sometimes and isn't very intuitive.
The picture menu contains most of the useful
settings. You can control the hardware aspect ratio here, brightness, contrast
etc. Also there's the control over the
response time,
dynamic contrast ratio and gamma preset. The pixel orbiting function is a
measure designed to reduce the chances of image burn in. The screen actually
gives you warning messages as well about burn in. Pixel orbiting is usually used
on plasma backlit screens, but it's been included here on this LED backlit
model. Maybe it's a panel which is prone to issues with image retention,
maybe Philips are just being cautious. Best to leave that turned on, and also set
a monitor turn off timer in your Operating system after a period of inactivity.
If nothing else that will help with your energy saving.
The PiP/PbP menu controls all the MultiView
settings if you are using multiple inputs.
The audio menu controls the speakers and the audio
source.
The color menu has a couple of useful options. You
can choose from a series of preset colour temp modes here, or enter the
factory
calibrated sRGB mode, or a user define mode where you can alter the RGB levels
yourself. More on that
later in the review.
The other sections shown above are pretty self
explanatory.
Important 4k Note: One thing to note is
that the screen comes as default set at DisplayPort mode 1.1. This will only
support 3840 x 2160 at 30Hz maximum, so if your graphics card supports DP 1.2
you need to go into this section and change the setting to 1.2. This will then
allow you to set the screen at the full 60Hz refresh rate in Windows. The screen is
detected as a single display (Single Stream Transport, SST) as opposed to MST
for those interested.
There is a hidden factory menu which can be
accessed by holding the joystick away from the power button (right if seen from
the front, left if seen from the rear), as you turn on the screen. Once on, go
into the normal OSD and there's a new section at the bottom. Changes are not
advised and are
entirely at your own risk.
Power Consumption
In terms of power consumption the manufacturer
lists 77.6W typical usage, 140W maximum usage and <0.5W in standby. We carried out our normal tests to
establish its power consumption ourselves.
State and Brightness
Setting
Manufacturer Spec (W)
Measured Power Usage
(W)
Factory Default (100%)
77.6
81.0
Calibrated (34%)
-
49.0
Maximum Brightness (100%)
140.0
81.0
Minimum Brightness (0%)
-
35.1
Standby
<0.5
0.8
We tested this ourselves and found that out of the
box the screen used 81.0W at the default 100% brightness setting. Maximum usage
specified would presumably be with USB connected etc as well. Once calibrated
the screen reached 49.0 W consumption, and in standby it used only 0.8W. We have plotted these
results below compared with other screens we have tested:
Panel and Backlighting
Panel Manufacturer
TP Vision
Colour Palette
16.7 million
Panel Technology
VA (Vertical Alignment)
Colour Depth
8-bit
Panel Module
TPT400LA-K1SQ1.N Rev:SC1A
Colour space
Standard Gamut
Backlighting Type
W-LED
Colour space coverage (%)
~sRGB, 72% NTSC
Panel Part and Colour Depth
The Philips BDM4065UC utilises an unusual panel
from a manufacturer we've not seen before. The panel is made by TP Vision, who
are
affiliated with TPV Technology and Philips. So effectively it's a Philips-own
panel used here. It is Vertical Alignment (VA) technology and the panel part is
the TPT400LA-K1QS1.N Rev: SC1A. The panel is capable of producing 16.7
million colours. This is achieved with an 8-bit colour depth. The panel is
confirmed when dismantling the screen as shown below, as well as within the OSD
factory menu:
Screen Coating
The
screen coating on BDM4065UC is a glossy solution. It has moderate levels of
reflection very similar to a lot of modern LCD TV's really. It's not overly
reflective like some glass fronted desktop displays we've seen in the past (Dell
S2440L / S2740L for instance) so it's pretty easy to work with. Being glossy it
does provide a nice clear and crisp image and it helps make colours and blacks
pop somewhat.
Backlight Type and Colour Gamut
The screen uses a White-LED (W-LED) backlight unit
which has become very popular in today's market. This helps reduce power
consumption compared with older CCFL backlight units and brings about some
environmental benefits as well. The W-LED unit offers a standard colour gamut
which is approximately equal to the sRGB colour space, and equating to ~72%
NTSC. Anyone wanting to work with wider colour spaces would need to consider
wide gamut backlit displays
instead.
Backlight
Dimming and Flicker
We tested the screen to establish the methods used
to control backlight dimming. Our in depth article talks in more details about a
common method used for this which is called
Pulse Width Modulation (PWM). This in itself gives cause for concern to some
users who have experienced eye strain, headaches and other symptoms as a result
of the flickering backlight caused by this technology. We use a photosensor +
oscilloscope system to measure backlight dimming control
with a high level of accuracy and ease. These tests allow us to establish
1) Whether PWM is being used to control the
backlight
2) The frequency and other characteristics at which this operates, if it is used
3) Whether a flicker may be introduced or potentially noticeable at certain
settings
If PWM is used for backlight dimming, the higher
the frequency, the less likely you are to see artefacts and flicker. The duty
cycle (the time for which the backlight is on) is also important and the shorter
the duty cycle, the more potential there is that you may see flicker. The other
factor which can influence flicker is the amplitude of the PWM, measuring the
difference in brightness output between the 'on' and 'off' states. Please
remember that not every user would notice a flicker from a backlight using PWM,
but it is something to be wary of. It is also a hard thing to quantify as it is
very subjective when talking about whether a user may or may not experience the
side effects.
100%
50%
0%
Above: scale =
1ms per horizontal grid
Above: scale =
10ms per horizontal grid
At 100% brightness a constant voltage is applied
to the backlight as you would expect. As you reduce the brightness setting a
Pulse Width Modulation technique is used for backlight dimming. This operates at
a low and fixed 240Hz throughout the brightness adjustment range, and the duty cycle (on
time) is just reduced as you lower the brightness setting. This low frequency
PWM dimming could present some problems to those with sensitive eyes or those
prone to issues with flicker.
We wanted to see how much variance there was in
the screens contrast as we adjusted the monitor setting for brightness.
In theory, brightness and contrast are two independent parameters, and good
contrast is a requirement regardless of the brightness adjustment.
Unfortunately, such is not always the case in practice. We recorded the
screens luminance and black depth at various OSD brightness settings, and
calculated the contrast ratio from there. Graphics card settings were left at
default with no ICC profile or calibration active. Tests were made using an
X-rite i1 Display Pro colorimeter. It should be noted that we used the
BasICColor calibration software here to record these, and so luminance at
default settings may vary a little from the LaCie Blue Eye Pro report.
OSD
Brightness
Luminance
(cd/m2)
Black
Point (cd/m2)
Contrast
Ratio
( x:1)
100
280.21
0.05
5604
90
256.07
0.05
5121
80
230.60
0.05
4612
70
205.60
0.04
5140
60
179.10
0.04
4478
50
150.77
0.03
5026
40
128.77
0.03
4292
30
106.67
0.02
5334
20
81.66
<0.02
-
10
57.95
<0.02
-
0
32.37
<0.02
-
Total Luminance Adjustment Range
(cd/m2)
247.84
Brightness OSD setting controls backlight?
Total Black Point
Adjustment Range (cd/m2)
>0.03
Average Static Contrast Ratio
4951:1
PWM Free?
Recommended OSD setting for 120 cd/m2
36
Tests were carried out at default screen settings.
The brightness control gave us a very good range of adjustment. At the top end
the maximum luminance reached 280.21
cd/m2 which was
only just shy of the specified maximum brightness of 300 cd/m2 by the
manufacturer. There was a 247.84 cd/m2 adjustment range in total,
and so at the minimum setting you could reach down to a nice low luminance of
32.37 cd/m2. This should be more than adequate for those wanting to
work in darkened room conditions with low ambient light. A setting of ~36 in the OSD menu should return you a
luminance of around 120 cd/m2 at default settings.
We have plotted the
luminance trend on the graph above. The screen behaves as it should in this
regard, with a reduction in the luminance output of the screen controlled by the
reduction in the OSD brightness setting. This was pretty much a linear relationship
as you can see from the shape of the graph. It should be noted that the brightness regulation is controlled using
Pulse Width Modulation at all brightness settings below 100, and at a low
frequency of 240Hz. This could be problematic to those prone to eye fatigue or
headaches associated with flickering backlights. Not everyone is affected of
course, but we advise caution. The average contrast ratio of the screen was
an amazing 4951:1. We have not included the contrast stability graph as rounding
errors lead to discrepancies with such a low black point measurement. Below a
setting of ~25 brightness the black depth becomes too low to be measured by our i1 Display
Pro device, which is why we've listed it as <0.02 in the table for settings
below 30.
Testing
Methodology
An
important thing to consider for most users is how a screen will perform out of
the box and with some basic manual adjustments. Since most users won't have
access to hardware colorimeter tools, it is important to understand how the
screen is going to perform in terms of colour accuracy for the average user.
I
restored my graphics card to default settings and disabled any previously active
ICC profiles and gamma corrections. The screen was tested at default factory settings using the DVI interface, and analysed using
an
X-rite i1
Pro Spectrophotometer (not to be confused with the i1 Display Pro
colorimeter) combined with
LaCie's Blue Eye Pro software suite. An X-rite i1 Display Pro colorimeter was
also used to verify the black point and contrast ratio since the i1 Pro
spectrophotometer is less
reliable at the darker end.
Targets for these tests are as follows:
CIE Diagram - validates the colour space
covered by the monitors backlighting in a 2D view, with the black triangle representing the
displays gamut, and other reference colour spaces shown for comparison
Gamma - we aim for 2.2 which is the default
for computer monitors
Colour temperature / white point - we aim
for 6500k which is the temperature of daylight
Luminance - we aim for 120
cd/m2, which is
the recommended luminance for LCD monitors in normal lighting conditions
Black depth - we aim
for as low as possible to maximise shadow detail and to offer us the best
contrast ratio
Contrast ratio - we aim
for as high as possible. Any dynamic contrast ratio controls are turned off here
if present
dE average / maximum -
as low as possible.
If DeltaE >3, the color displayed is significantly different from the
theoretical one, meaning that the difference will be perceptible to the
viewer.
If DeltaE <2, LaCie considers the calibration a success; there remains a
slight difference, but it is barely undetectable.
If DeltaE < 1, the color fidelity is excellent.
Default Performance and
Setup
Default settings of the screen were as follows:
Monitor OSD Option
Default Settings
Brightness
100
Contrast
50
Smart Image preset mode
Off
Color Temperature
6500k
Gamma
2.2
Philips BDM4065UC - Default Factory Settings
Default Settings
luminance (cd/m2)
298
Black Point (cd/m2)
0.05
Contrast Ratio
5604:1
Out of the box the screen looked reasonable to
the naked eye. Colours felt even and well balanced if perhaps slightly too blue.
The brightness was too high as the brightness setting was maxed out at 100. We went ahead and measured
the default state with the i1 Pro.
The
CIE diagram on the left of the image confirms that the monitors colour gamut
(black triangle) matches the sRGB colour space very well, with some minor
over-coverage in blue shades being evident. Default
gamma was recorded at 2.2 average, leaving it with a very minor 2% deviance from
the target of 2.2 which was pleasing. White point was measured at 7077k leaving it a
moderate 9% out from our target of 6500k and being a little too cool.
Luminance was recorded at a very bright 298
cd/m2 which is
too high for prolonged general use. The screen was set
at a default 100% brightness but that is easy to change of course
to reach a more comfortable setting without impacting other aspects of the setup. The black depth was
an incredibly low 0.05 cd/m2 at this default
brightness setting, giving us an amazing static contrast ratio of
5604:1.
Colour accuracy was reasonable out of the
box with a default dE of 2.4, but a maximum of 8.7 in blue shades. Testing the screen with
various gradients showed smooth transitions with no sign of any banding
thankfully. There was some very slight gradation evident in darker tones as you
will see from most monitors. Overall the default setup was pretty decent and we
were impressed certainly by the very high contrast ratio from the VA panel.
Monitor OSD Option
Default Settings
User define mode
Brightness
100
Contrast
50
Smart Image preset mode
Off
Color Temperature
User Define
Gamma
2.2
RGB
100, 100, 100
Philips BDM4065UC - Default Settings, User Define mode
Default Settings
User define mode
luminance (cd/m2)
308
Black Point (cd/m2)
0.05
Contrast Ratio
5840:1
We also tested the default 'user define' mode. In the
user define mode you are able to change the RGB levels manually if you want
which we will use in the following calibration section. By default they are all
set at 100 each. In this mode you will note the slightly higher static contrast
ratio and brightness, since the RGB levels are all maxed out. Unfortunately by
default the colour temperature in this mode is way off, being very cool visually
and measured by our i1 Pro at 9539k (47% deviance). If we are to use this mode
we will need to adjust the RGB channels to get a more accurate white point
closer to the desired 6500k and bring the blue gain down significantly.
Update Note 18 March 2016
We've had a few readers contact us in recent
months about an issue some people have experienced with the screen where colours
appear to "bleed" in to other areas of the screen. The
above Youtube video
gives a good demonstration of the issue reported. We didn't experience this on
our test unit when we reviewed it back in 2014, although we weren't specifically
looking for it so it's hard to say 100% whether the unit was affected or not. We
certainly didn't notice these kind of problems on that sample in day to day
normal uses and throughout the course of our testing. If you do buy this screen
and find you are affected in your uses, we would recommend returning it or
attempting a replacement with Philips. We are referencing this issue here for
completeness more than anything.
Factory Calibration
Monitor OSD Option
Default Settings
sRGB mode
Brightness
100
Contrast
50
Smart Image preset mode
Off
Color Temperature
sRGB
Gamma
2.2
Philips BDM4065UC - Default Settings, sRGB mode
Default Settings,
sRGB mode
luminance (cd/m2)
297
Black Point (cd/m2)
0.05
Contrast Ratio
5622:1
We also wanted to test the factory calibrated sRGB
mode which is available within the 'color' section of the OSD menu. When you
enable this mode, the brightness setting is actually locked at 100. If you try
and change the setting it tells you it is going to revert back to the 6500k mode
as before. That's a shame as you can see the sRGB mode actually offered a more
reliable default setup. Being bound to a maximum brightness though makes it
rather pointless and not something you can comfortably use day to day. This mode
offered a white point closer to the 6500k target, being measured at 6779k with a
4% deviance. Colour accuracy was also a bit better with less deviance in the
blue shades now. This would have been a useful mode for colour work if you'd
been able to adjust the brightness setting in the OSD menu.
Calibration
We used the
X-rite i1 Pro spectrophotometer combined with the LaCie Blue Eye Pro
software package to achieve these results and reports. An X-rite i1 Display Pro
colorimeter was used to validate the black depth and contrast
ratios due to lower end limitations of the i1 Pro device.
Monitor OSD Option
Calibrated Settings
Brightness
34
Contrast
50
Smart Image preset mode
Off
Color Temperature
User Define
Gamma
2.2
RGB
100, 99, 84
Philips BDM4065UC - Calibrated Settings
Calibrated Settings
luminance (cd/m2)
120
Black Point (cd/m2)
0.03
Contrast Ratio
4128:1
We stuck with the 'user define' color
mode in the OSD menu which allowed us access to the individual RGB channels. Adjustments were made during the process to the RGB channels as shown in the table above
as well as the brightness control. This allowed us to obtain an
optimum hardware starting point and setup before software level changes would be
made at the graphics card level.
We left the LaCie software to calibrate to "max"
brightness which would just retain the luminance of whatever brightness we'd set
the screen to, and would not in any way try and alter the luminance at the
graphics card level, which can reduce contrast ratio. These adjustments before
profiling the screen would help preserve tonal values and limit banding issues.
After this we let the software carry out the LUT adjustments and create an
ICC profile.
Average gamma had been corrected spot on to 2.2 average, correcting
the minor 2% deviance we'd
found out of the box which was good. The white point was also
corrected to 6487k,
correcting the moderate 9% deviance we'd seen before as well in the 6500k
default mode. You will note that we have massively reduced the blue channel here
to make the image warmer than the default user define mode which was far too
cool. Luminance had also
been improved thanks to the adjustment to the brightness control and was now
being measured at 120
cd/m2. This
left us a black depth of 0.03 cd/m2 and an excellent static contrast ratio of
4128:1. This was lower than the out of the box settings since we had adjusted
the RGB channels now, and also corrected the white point through the graphics
card profiling. It was still an excellent static contrast ratio though. Colour
accuracy had been corrected nicely also, with dE average of 0.7 and maximum of
1.3. LaCie would consider colour fidelity to be excellent.
Testing the screen with various colour gradients
showed smooth transitions. There was some very slight gradation in darker tones
but no banding was introduced which can often happen where adjustments are made to the
graphics card LUT from the profilation of the screen.
You can use our settings and
try our calibrated ICC profile if you wish, which are available in
our ICC profile database. Keep in mind that results will vary from one
screen to another and from one computer / graphics card to another.
Calibration
Performance Comparisons
The comparisons made in this section try to give
you a better view of how each screen performs, particularly out of the box which
is what is going to matter to most consumers. When comparing the default factory
settings for each monitor it is important to take into account several
measurement areas - gamma, white point and colour accuracy. There's no point
having a low dE colour accuracy figure if the gamma curve is way off for
instance. A good factory calibration requires all 3 to be well set up. We have
deliberately not included luminance in this comparison since this is normally
far too high by default on every screen. However, that is very easily controlled
through the brightness setting (on most screens) and should not impact the other
areas being measured anyway. It is easy enough to obtain a suitable luminance
for your working conditions and individual preferences, but a reliable factory
setup in gamma, white point and colour accuracy is important and not as easy to
change accurately without a calibration tool.
From these comparisons we can also compare the
calibrated colour accuracy, black depth and contrast ratio. After a calibration
the gamma, white point and luminance should all be at their desired targets.
Default setup of the screen was pretty decent
overall. Gamma was accurate, colour accuracy dE was nice and low and we had an
amazing contrast ratio thanks to the VA panel. The white point let it down a
little as it was 9% out from the target and a bit too cool. Easy enough to
adjust and correct through calibration though which was good news.
The panel did extremely well in terms of black depth and
contrast ratio, with a calibrated contrast ratio of 4128:1
measured. In the past we've seen common AMVA contrast ratios of around 2000 -
3000:1 from panels manufactured by AU Optronics. The Eizo FG2421 had reached
4845:1 with its Sharp MVA panel. Here, the TP Vision VA panel of the Philips BDM4065UC
reached up to 4128:1 after calibration. Contrast ratio was an obvious strong
point of this panel, far out-doing anything which TN Film or IPS-type panels
can offer (up to around 1000:1 in best cases).
Viewing Angles
Above: Viewing
angles shown from front and side, and from above and below. Click for
larger image
Viewing angles of the BDM4065UC were quite
comparable to other VA panels we've seen in the past.
Horizontally the viewing angles were not bad. As
you moved you line of sight past about 45� contrast shifted and a pale tint
appeared on the image. The image got progressively more washed out as you moved
further away from a central point of view. On some older AMVA panels the image
tends to go very yellow from a wide horizontal angle but on the BDM4065UC it
just went pale and washed out instead. Vertically the contrast shift was more
pronounced and the image became more washed out from a shorter angle. This was
actually apparent slightly when using the screen from a couple of feet away on a
normal desktop position. Being pretty tall, my line of sight was about 3/4 of
the way up the screen if I looked head on. If I glance towards the bottom of the
screen the image becomes slightly washed out due to the viewing angles. If you
move further back from the screen for movies or games, you don't see this, it's
only when up close and due to the sheer size of the screen.
Viewing angles were not as wide as IPS or PLS
panels as you might expect given this is a VA matrix. They were not too bad
though compared with a lot of other VA panels out there which was pleasing. The
contrast shifts were evident here from wider angles, but there was very little
colour tone shift thankfully which is far more noticeable on most other VA
panels. Being VA based the panel did suffer from the off-centre contrast shift
you will see from these technology panels. If you view a very dark grey image
with a black background head on, the grey content is somewhat lost in the image
and appears darker than intended. Only as you move your line of sight slightly
away from a head on central field of view does the grey content appear again.
This is common of all VA matrices, and is one of the reasons why IPS is so
popular for colour critical work. It should be noted that not everyone would
even see this issue or be bothered by it. The viewing angles are certainly much
better than TN Film panels of course.
Above: View of an
all black screen from the side. Click for larger version
On a black image there was a slight pale glow from
an angle but it was nothing really bad at all. Certainly you don't get the
obvious white glow you see on a lot of IPS and PLS panels when viewing dark
content from an angle. From that point of view this is one area where VA panel
viewing angles are preferred.
We wanted to test
here how uniform the brightness was across the screen, as well as identify any
leakage from the backlight in dark lighting conditions. Measurements of the
luminance were taken at 35 points across the panel on a pure
white background. The measurements were taken using BasICColor's calibration
software package, combined with an X-rite i1 Display Pro
colorimeter with a central point on the screen calibrated to 120 cd/m2. The below uniformity diagram shows the difference, as a percentage,
between the measurement recorded at each point on the screen, as compared with the
central reference point.
It is worth
noting that panel uniformity can vary from one screen to another, and can depend
on manufacturing lines, screen transport and other local factors. This is only a
guide of the uniformity of the sample screen we have for review.
Uniformity of Luminance
The luminance uniformity of the screen was
moderate overall although there were clearly some areas which were much
darker than the rest. The 4 corners seemed to be the problem, where
luminance dropped down by a maximum of ~35% to 89
cd/m2
in the most extreme example. The central zones of the screen were more
uniform and around 48% of the screen was within a 10% deviance from the
centrally calibrated 120 cd/m2 point. This wasn't great
unfortunately. Not likely to be an issue for gaming and movies, but perhaps problematic if you were wanting to do any
colour critical work with large colour patches.
Uniformity of Luminance
Smart Uniformity = On
The BDM4065UC also features a uniformity
correction mode which according to the spec should offer uniformity of 96 -
105%. This is accessed through the preset mode menu using the
"SmartUniformity" option. As you can see, some of the uniformity issues have
been improved now. The upper corner regions of the screen were a bit
brighter than the central zone, ranging up by 11% in the most extreme cases
which wasn't bad really. Around 97% of the screen was now within a 10%
deviance from the centrally calibrated point which was far better and
actually a very good result. This uniformity correction feature seemed to
work very nicely and we imagine users might want to use this, certainly for
any colour critical work they might be doing. This does beg the question
though as to whether this mode has an impact on other aspects of the image.
We went back to measure the setup in this mode:
You can use each of the different color modes
still while in this new preset mode, and the screen defaults back to the defined
6500k colour temperature mode first of all. You can use the 'user define' mode
still and adjust the RGB channels yourself which we will look at in a moment.
Unfortunately while the SmartUniformity mode offers an improvement to the
uniformity of the screen, some other areas are impacted negatively. At 100
brightness, we are now limited to a maximum luminance of 198
cd/m2. Not actually a bad thing as the maximum before was ~ 300 cd/m2.
We did have a reduced contrast ratio though, down from 5604:1 when the setting
was off (everything else the same as it is here), to 3951:1 now. Still a very
high contrast ratio of course. Gamma had unfortunately now strayed away from our
2.2 target, with an average of 2.0 measured leaving an 11% deviance. White point
was also cooler even than before, with a 7662k white point measured, leaving an
18% deviance. Colour accuracy was close to the default 6500k mode when
SmartUniformity was off, with dE average pf 2.8 and maximum of 6.0. The gamma
and white point deviance was the main sacrifices made when switching to this
uniformity correction mode we felt and you will need to do some calibration to
correct those.
We went ahead and calibrated the screen again,
this time with SmartUniformity turned on. We reverted back to the 'user define'
color mode to give us control over the RGB channels, and we again had to bring
the blue gain down a lot to compensate for the cool default setting. If nothing
else, the changes to the OSD settings should get you to a more accurate white
point, but profilation using a calibration tool will be necessary to correct the
gamma curve and make some more advanced adjustments. After calibration we had
reached the gamma and white point targets nicely. You will need to have
brightness set ~58 to achieve the desired luminance when you have
SmartUniformity enabled. Colour accuracy had been corrected pretty nicely,
although there did seem to be some deviance in reds where dE reached up to 2.8.
This didn't seem to be possible to correct fully.
The SmartUniformity mode did offer improvements to
the screens uniformity so we would recommend switching to that mode certainly
for any colour critical work. That is on the assumption that you have a
calibration device or some way to correct the resulting gamma and white point
though, as these are further out from the targets than when you have
SmartUniformity off. You can of course use our calibrated settings and try our
ICC profile which might help
improve things for you anyway.
Backlight Leakage
Above: All black screen in a darkened room. Click for larger version
As usual we also tested the screen with an all
black image and in a darkened room. A camera was used to capture the result.
Three was no noticeable backlight bleed or clouding at all, and the screen
offered very deep and dark blacks thanks to its VA panel.
General and Office Applications
The BDM4065UC is a very interesting option for
desktop use. The quad HD 3840 x 2160 resolution is well suited to a screen as
big as this and offers a comfortable pixel pitch and font size by default,
without the need to do OS scaling. We
had previously found the text size and pixel pitch a little too small when we
tested the 31.5" sized
Dell UP3214Q and certainly very tiny when we tested the 28" sized
Samsung U28D590D. You can of course use various scaling methods to make 4k
resolutions more usable on smaller screens, but it's not always easy to get
something set up for all your uses. While some Operating systems scale well,
others do not, and a lot of apps also have problems with the scaling. Here on
the BDM4065UC you don't need to bother with scaling at all, you can just run the
screen and operating system at it's normal settings without the text being too small. The pixel pitch of 0.2281 mm is very comparable to the 0.2331 mm of a
27" 2560 x 1440 resolution panel. This is perfectly fine for day to day use.
With the high resolution and huge screen size you have plenty of room for
multi-tasking and split screen working which is great news. For word processing,
CAD/CAM, image editing, programming etc it's really a massive area to use.
You do need to keep in mind the need for a
compatible graphics card with a suitable output which can handle this
resolution, and preferably at 60Hz refresh rate. DisplayPort is the only option
to run the screen at its native 3840 x 2160 res at 60Hz, so is certainly
recommended. When running at native resolution this model is recognised as a
single display which makes life easier than some of the early MultiStream (MST)
4k models. It's also good to see support for 60Hz refresh rate as some 4k models
only offer 30Hz support which is very limiting, even in day to day uses
(certainly for gaming!).
The glossy AG coating of the panel provides
clear and crisp images. It is not overly reflective like some glass-fronted
screens for instance, but there's no graininess of any kind from an AG coating
here. The
reasonably
wide viewing angles provided by the VA panel technology helps minimize on-screen colour shift when viewed from different angles.
The vertical angles are somewhat restrictive though and you can notice some
colour washout vertically when using the screen up close.
The
default setup of the screen was pretty good in most areas, with only brightness
needing to be turned down to something more comfortable (which doesn't affect
other aspects of the setup) and some minor correction to the white point needed.
The contrast ratio was excellent thanks to the VA panel, and certainly a major
strong point of this panel. The SmartUniformity mode improved the uniformity of
the panel nicely, but the default setup of this mode needs some further tweaking
to get to a more reliable setup. The factory calibrated sRGB mode offered a very
good setup, but with brightness locked at 100% in that mode it renders it
unusable.
The brightness
range of the screen was very good, with the ability to offer a luminance
between 280 and 32 cd/m2. This should mean the screen is perfectly
useable in a wide variety of ambient light conditions, including darkened rooms.
A setting of ~36 in the OSD brightness
control should return you a luminance close to 120 cd/m2 out of the
box. On a less
positive note, the brightness regulation is controlled using
the now
infamous
Pulse-Width Modulation (PWM), for all settings below 100 unfortunately. This
operates at a low 240Hz frequency as well so could present problems to some
users who are affected by flickering backlights. There was no
audible noise or buzzing from the screen, even when specifically looking for it
using test images with a large amount of text at once. The screen also remains
pretty cool even during prolonged use. There are no specific paper/reading type
preset modes available from the OSD menu on this model.
The screen offers 4x USB 3.0 ports which can be
useful and it was nice to keep this up to date with the modern version. There
are also some further extras including one of those ports supporting
fast-charge, audio input/output connections, integrated 2x 7W stereo speakers
and a whole range of PiP and PbP options. One major drawback of the screen is
the lack of any ergonomic adjustments from the stand, not even tilt. We felt the
screen was too upright for close proximity office working so you will either
need to prop something under the front of the stand to tilt it back a bit, or
wall/arm mount the screen via the VESA 200mm holes.
Above: photo of
text at 3840 x 2160 (top) and 1920 x 1080 (bottom)
The screen is designed to run at its native
resolution of 3840 x 2160 and at a 60Hz recommended refresh rate. However, if
you want you are able to run the screen outside of this resolution. We tested
the screen at a lower 1920 x 1080 resolution to see how the screen handles the
interpolation of the resolution, while maintaining the same aspect ratio of
16:9. At native resolution the text was sharp as you can see from the top
photograph. There did appear to be some slight overlapping of pixels but you
couldn't spot this during normal use. When you switch to a lower resolution the text is larger of course
but still pretty clear, with low levels of blurring introduced. The screen seems to interpolate the image
quite well although you of
course lose a lot of desktop real-estate running at a lower resolution. This is
at least positive news for if you want to game or watch content from an external
device at 1080p.
Responsiveness and Gaming
Quoted G2G Response Time
8.5ms G2G
3ms G2G (SmartResponse )
Quoted ISO Response Time
n/a
Panel Manufacturer and
Technology
TP Vision VA
Panel Part
TPT400LA-K1QS1.N Rev: SC1A
Overdrive Used
Yes
Overdrive Control Available to
User
'SmartResponse'
Overdrive Settings
Off, Fast, Faster, Fastest
The BDM4065UC is rated by Philips as having an 8.5ms G2G response time
and the panel uses
overdrive /
response time compensation (RTC) technology to boost pixel transitions
across grey to grey changes. They also list an adventurous 3ms G2G figure for
when using the 'SmartResponse' setting, which is basically an overdrive control.
There are options for this overdrive setting for off, fast, faster and fastest. The
part
being used is the
TP Vision TPT400LA-K1QS1.N Rev: SC1A panel. Have a read about response time in
our
specs section if you need additional information about this measurement.
We will first test the screen using our thorough
response time testing method. This uses an oscilloscope and photosensor to
measure the pixel response times across a series of 20 different transitions, in
the full range from 0 (black) to 255 (white). This will give us a realistic view
of how the monitor performs in real life, as opposed to being reliant only on a
manufacturers spec. We can work out the response times for changing between many
different shades, calculate the maximum, minimum and average grey
to grey (G2G) response times, and provide an evaluation of any overshoot present
on the monitor.
Response Time Setting Comparison (SmartResponse
option)
The BDM4065UC comes with a user control for the
overdrive impulse available within the OSD menu in the picture section of the menu as shown above. There are
four options under the
'SmartResponse' setting. First of all we carried out a smaller sample set of
measurements in all three of the settings. These, along with various motion
tests allowed us to quickly identify which was the optimum setting for this
screen.
With the setting turned off, the pixel transitions
were actually good for a VA panel and we were impressed. There was an average
8.0ms G2G response time measured here which was pleasing. There was one
transition measured which seemed to be problematic, the change from black to
white (0-255) where there was a stepping in the brightness curve and it took a
while to reach the desired luminance. The rest of the transitions were faster
and averaged ~7.1ms G2G. There was no overshoot with the overdrive control set
to off which was pleasing.
Pushing the overdrive setting up to 'Fast'
brought about some changes. Response times were a bit better now with an average
of 6.4ms G2G measured. The 0-255 transition was still a problem, as that
transition already had the maximum voltage applied to it anyway (since it's the
most extreme change in pixel orientation), and so there was nothing more that
the overdrive impulse could do. While additional voltages were being applied to
overdrive the other transitions, this was still stuck with a slow response time.
If we ignored this slow transition the response times would be more like ~5.3ms
G2G. Unfortunately even with this first overdrive setting (Fast) there was some
significant and noticeable overshoot introduced. This was at a high level and so
this mode should probably be avoided. You can spot nasty trailing in moving
images and it's a shame this first overdrive setting wasn't a bit more modest.
We would expect aggressive overshoot from the higher overdrive settings, but not
from this first step!
With overdrive pushed up to the 'Faster' setting
there was another reduction in response times, down to 5.5ms G2G average.
Overshoot was now horrendous though and certainly even more noticeable in
practice.
The 'Fastest' mode pushed things even further, and
the overshoot was massive. This should certainly be avoided.
Transition: 0-255-0 (scale = 20ms),
SmartResponse = Off
To show that the 0-255 transition was always slow
no matter which overdrive setting you use, you can compare the graphs for
SmartResponse 'off' and 'Fastest' above. The stepping of the brightness curve
resulted in a slow rise time on this transition.
If we also carry out some subjective assessment of
the screen during gaming and with the use of the PixPerAn moving car tests, we
can also see the differences between each overdrive mode easily enough with the
naked eye. With SmartResponse (overdrive) off there was low levels of blurring
to the moving image and no sign of any overshoot. As you push the overdrive
control up to fast, a noticeable dark overshoot is evident. This gets
progressively worse as you move up to 'faster' and 'fastest' to the point where
it is very distracting and problematic. The 'off' setting seems to be the
optimum here, offering actually pretty good response times and no overshoot at
all. The other modes are just too aggressive and there's too much overshoot
introduced, even at the lowest of the settings (Fast).
More Detailed Measurements - SmartResponse Off
Having established that the overdrive 'off'
mode seemed to offer the best response/overshoot balance we carried out our
normal wider range of measurements as shown below:
The average G2G response time was now more
accurately measured at a pretty impressive 7.4ms. This was good for a VA panel.
Rise and fall times were on average very comparable. The 0-255 (black > white)
transition was the only slow transition measured, dragging the overall average
down. Some response times actually reached very low levels, down to 2.3ms in the
best case which was very impressive for a VA panel. The panel was living up to
its spec of 8.5ms G2G quite easily, and even in some cases reaching down below
the quoted 3ms G2G figure applicable for when you have SmartResponse enabled.
If we evaluate the Response Time Compensation
(RTC) overshoot then the results are pleasing and there is very little to be
seen at all. A couple of the measured transitions showed a some very low levels
of overshoot but nothing you'd notice in practice at all. A pleasing result
here.
Display Comparisons
The above comparison table and graph shows you the
lowest, average and highest G2G response time measurement for a selection of
screens we have tested with our oscilloscope system. There is also a colour
coded mark next to each screen in the table to indicate the RTC overshoot error,
as the response time figure alone doesn't tell the whole story.
The response time performance of the BDM4065UC was
impressive for a VA type panel, even when you consider we had to stick with the
overdrive setting turned off to avoid a mass of overshoot artefacts. With a
7.4ms G2G average it was even a bit faster than the gamer-orientated Eizo Foris
FG2421 (8.4ms average), as long as we consider all the recorded transitions. The
Eizo had been affected by a couple of particularly slow transitions. If we were
to ignore the most extreme cases on the FG2421 and on the BDM4065UC the response
times would be far closer, and both would be around the 6.6 - 7.0ms G2G mark.
Anyway, the point we are trying to make is that this is fast for a VA panel.
Other VA panels like the BenQ GW2760HS and BenQ BL3200PT had been slower at
around 10.8 - 10.9ms G2G. The Philips is even a bit faster than the best IPS
panels we've tested. In the best examples, where no overshoot is introduced, IPS
models like the Dell U2415 can reach down to around 8.6ms G2G average. A good TN
Film model is of course still faster, reaching down to 2.9ms
for instance in the example of the new
Asus ROG Swift PG278Q (with moderate overshoot). They also have additional
gaming features like higher refresh rates, blur reduction modes etc. For a VA
panel this was a good response time performance though.
The screen was also tested using the chase test in
PixPerAn for the following display comparisons. As a reminder, a series of
pictures are taken on the highest shutter speed and compared, with the best case
example shown on the left, and worst case example on the right. This should only
be used as a rough guide to comparative responsiveness but is handy for a
comparison between different screens and technologies as well as a means to
compare those screens we tested before the introduction of our oscilloscope
method.
40"
8.5ms G2G TP Vision VA (SmartResponse = Off)
In practice the Philips BDM4065UC showed pretty low
levels of motion blur, and no obvious ghosting. There was some some slight
trailing in the best case images as you can see above but overall the movement
felt quite good. There was no sign of any overshoot artefacts either
which was pleasing in the SmartResponse = off mode. Of course you do need to keep in mind this is a
VA panel,
and so does not feel as snappy as a fast TN Film panel, and cannot offer the
response time of that panel technology either. Other limiting factors also come
into play including the refresh rate (limited to 60Hz here) and motion blur as a
result of eye-tracking and the way LCD monitors operate. For an VA panel at
60Hz it is a decent result though.
40"
8.5ms G2G TP Vision VA (SmartResponse = Off)
34"
5ms
G2G LG.Display AH-IPS (Response Time = Middle)
28"
1ms
G2G Innolux TN Film (Overdrive = Faster)
31.5"
8ms G2G Sharp IPS-mode IGZO
If we compare the BDM4065UC to the other 4k res
screens we've tested (well, 3840 x 1080 from the LG 34UM95) we can see some
varying levels of performance from each panel technology. In practice the
BDM4065UC performs fairly similarly to the LG 34UM95 with its IPS panel. The LG
has slightly slower response times (9.5ms G2G) and in practice the blurring is a
little more pronounced than on the Philips (7.4ms G2G). The Samsung U28D590D has
a TN Film panel and has a 7.0ms G2G response time, only slightly faster than the
Philips but nothing really to separate them in practice. The Dell UP3214Q is
aimed at professional users and its IGZO panel has a 11.2ms G2G response time,
showing a more apparent blur in moving images.
40"
8.5ms G2G TP Vision VA (SmartResponse = Off)
27" 2ms G2G Chi
Mei Innolux TN Film +144Hz (Trace Free = 60)
24" 2ms G2G AU
Optronics TN Film + 120Hz (AMA = On)
23.5" 4ms G2G
Sharp MVA + 120Hz
We've also included a comparison above against
3 very fast 120Hz+ compatible screens we have tested. The other screens shown
here are all aimed primarily at gamers and have various features and extras
which make them more suitable overall for gaming.
Firstly there is a comparison against the
Asus VG278HE with its 144Hz refresh
rate and fast response time TN Film panel. This showed very fast pixel response times and smooth movement thanks to
its increased refresh rate. You are able to reduce the motion blur even more
through the use of the LightBoost strobed backlight which we talked about in
depth in our article about
Motion Blur Reduction Backlights.
Then there is a comparison against the
BenQ XL2420T with another very fast TN Film panel and 120Hz refresh rate.
This showed very low levels of motion blur, but some dark overshoot was
introduced as a side-effect. Lastly there is the MVA based Eizo FG2421 screen
with a fast response time (especially for the panel technology being used) and
120Hz refresh rate support. There is also an additional 'Turbo 240' motion blur
reduction mode which really helps reduce the perceived motion blur in practice.
While these pixel response tests from PixPerAn show the
Philips to
have pretty fast pixel transitions and freedom from any overshoot, there is something else going on as well here which can't be picked out by the camera. All of these other
gaming models are
running at 120Hz (or higher) refresh rates, which allows for improved 120fps+ frame rates and
the support of
3D stereoscopic content as well. This can really help improve smoothness and
the overall gaming experience so these screens still have the edge when it comes
to fast gaming. Any additional extras to reduce perceived motion blur can also
have a real benefit in practical terms, and again not easy to pick out with this
camera method.
The responsiveness of the Philips BDM4065UC was
pleasing, and actually very good for a VA panel. The average 7.4ms G2G response time couldn't of course compete with fast
TN Film models, but for a VA panel it was good and also faster than IPS models
available. The freedom from
any overshoot problems was a major plus point but you do need to stick with
SmartResponse set to off. The screen should be able to handle some fast
gaming without problem, although those wanting to play fast FPS or competitive
games may want to consider some of the more gamer orientated 120Hz+, TN Film
based compatible displays out
there, or perhaps something like the Eizo FG2421. Even better still would be models equipped with
LightBoost systems or other motion blur reduction backlights for optimum motion blur elimination.
The massive 40" screen size really comes in to its
own when playing games. It adds a lot of immersion and you have a really huge
area to view. You can comfortably sit a few metres back from the screen like you
would with an LCD TV and play games. The Quad HD resolution is also very
impressive for games, providing a very high resolution and a lot of detail.
Images look sharp and crisp even up close. One
big consideration you need to make is that the 3840 x 2160 resolution is likely
to be a major drag on even high end graphics cards and PC systems when it comes
to gaming. You really need to think about the type of game you want to play, the
settings you want to use, and whether your system can handle outputting such a
high resolution effectively. Your graphics card will also need to support
DisplayPort 1.2 and you will need to enable this option in the OSD to obtain a
full 60Hz refresh rate over DisplayPort. Other interfaces including the HDMI
inputs are limited to 30Hz at 3840 x 2160. Don't forget that many gaming titles
don't support this 4k resolution either, so that could be another issue. At
least with those that do you don't need to worry about the size of fonts on a
screen this size like you do on smaller 4k models. Some games don't handle
scaling very well and so when it comes to the user interface a lack of scaling
results in tiny text or hard to read maps etc. That's not a problem here though
on the BDM4065UC.
One option of course is to run the game at a lower
resolution and let the screen scale it. That's probably the most sensible option
in most cases and we know that the interpolation of lower resolutions like 1920
x 1080 is actually pretty good on this model. It does kind of defeat the point
of having a 4k resolution in the first place though. If you have games which can
natively support this resolution properly, they would look fantastic given the
very high resolution and large screen size. External games consoles running at
1080p will still look fine of course, and the image is interpolated well, but
you will certainly want to be sitting a normal TV viewing distance to play those
we're sure.
Additional Gaming Features
Aspect Ratio Control - The screen offers
three options for hardware level aspect ratio control, available within the
'picture' section of the OSD menu. There areoptions for 'wide screen'
(which fills the screen at a 16:9 ratio), 4:3 and 1:1 pixel mapping. This should
offer adequate options for external devices and gaming needs.
Preset Modes - There is a defined 'game' preset mode available in the menu
which seems to accentuate the sharpness of the image quite a lot. It might be a
useful option to set up for your gaming needs and have a play around with.
Lag
We have written an in depth article about
input lag and the various measurement techniques which are used to evaluate
this aspect of a display. It's important to first of all understand the
different methods available and also what this lag means to you as an end-user.
Input Lag vs. Display Lag vs. Signal
Processing
To avoid confusion with different terminology we
will refer to this section of our reviews as just "lag" from now on, as there
are a few different aspects to consider, and different interpretations of the
term "input lag". We will consider the following points here as much as
possible. The overall "display lag" is the first, that being the delay between
the image being shown on the TFT display and that being shown on a CRT. This is
what many people will know as input lag and originally was the measure made to
explain why the image is a little behind when using a CRT. The older stopwatch
based methods were the common way to measure this in the past, but through
advanced studies have been shown to be quite inaccurate. As a result, more
advanced tools like SMTT provide a method to measure that delay between a TFT
and CRT while removing the inaccuracies of older stopwatch methods.
In reality that lag / delay is caused by a
combination of two things - the signal processing delay caused by the TFT
electronics / scaler, and the response time of the pixels themselves. Most
"input lag" measurements over the years have always been based on the overall
display lag (signal processing + response time) and indeed the SMTT tool is
based on this visual difference between a CRT and TFT and so measures the
overall display lag. In practice the signal processing is the element which
gives the feel of lag to the user, and the response time of course can
impact blurring, and overall image quality in moving scenes. As people become
more aware of lag as a possible issue, we are of course keen to try and
understand the split between the two as much as possible to give a complete
picture.
The signal processing element within that is quite
hard to identify without extremely high end equipment and very complicated
methods. In fact the studies by Thomas Thiemann which really kicked this whole
thing off were based on equipment worth >100,1000 Euro, requiring extremely high
bandwidths and very complicated methods to trigger the correct behaviour and
accurately measure the signal processing on its own. Other techniques which are
being used since are not conducted by Thomas (he is a freelance writer) or based
on this equipment or technique, and may also be subject to other errors or
inaccuracies based on our conversations with him since. It's very hard as a
result to produce a technique which will measure just the signal processing on
its own unfortunately. Many measurement techniques are also not explained and so
it is important to try and get a picture from various sources if possible to
make an informed judgement about a display overall.
For our tests we will continue to use the SMTT
tool to measure the overall "display lag". From there we can use our
oscilloscope system to measure the response time across a wide range of grey to
grey (G2G) transitions as recorded in our
response time
tests. Since SMTT will not include the full response time within its
measurements, after speaking with Thomas further about the situation we will
subtract half of the average G2G response time from the total display lag. This should allow us to give a good estimation of
how much of the overall lag is attributable to the signal processing element on
its own.
Lag Classification
To help in this section we will also introduce a broader classification system
for these results to help categorise each screen as one of the following levels:
Class 1)
Less than 16ms / 1 frame lag - should be fine for gamers, even at high levels
Class
2)A lag of 16 -
32ms / One to two frames - moderate lag but should be fine for many gamers.
Caution advised for serious gaming and FPS
Class
3)A lag of more
than 32ms / more than 2 frames - Some noticeable lag in daily usage, not
suitable for high end gaming
For the full reviews of the models compared here and the dates they were written
(and when screens were approximately released to the market), please see our
full
reviews index.
(Measurements in ms)
Total Display Lag (SMTT
2)
24.0
Pixel Response Time
Element
3.70
Estimated Signal
Processing Lag
20.30
Lag Classification
2
Class 2
We have provided a comparison above against other
models we have tested to give an indication between screens. The screens tested
are split into two measurements which are based on our overall display lag tests
(using SMTT) and half the average G2G response time, as measured by the
oscilloscope. The response time is split from the overall display lag and shown
on the graph as the green bar. From there, the signal processing (red bar) can
be provided as a good estimation.
The screen showed a total average display lag of
24.0 ms as measured with SMTT 2. Taking into account half the average G2G
response time at 3.7ms ('off' SmartResponse overdrive setting), we can estimate that
there is ~20.3 ms of signal processing lag on this screen. This is only just
over 1 frame and represents a moderate level of lag. Should be ok for most
gamers although some competitive or FPS type gamers might find it a bit too
high.
Movies and Video
The following summarises the screens performance
in video applications:
40"
screen size makes it a very decent size for an all-in-one multimedia screen,
being comparable to many current LCD TV's in fact. Truly massive for a desktop
display.
16:9
aspect ratio is more well suited to videos than a 16:10 format screen, leaving
smaller borders on DVD's and wide screen content at the top and bottom.
3840 x
2160 resolution can support full Quad HD ("4k") resolution content, as well as
1920 x 1080 of course.
2x HDMI and 1x DisplayPort
connections available, so good choices for modern DVD players, Blu-ray,
consoles etc. Good to see HDMI included here.
Cables provided in the box
for DisplayPort, HDMI, MHL/HDMI and VGA.
Glossy
screen coating providing clean and clear images, similar to many modern TV's.
The coating is not too reflective though.
Wide
brightness range adjustment possible from the display, including high maximum
luminance of ~280
cd/m2 and a low minimum
luminance of only 32 cd/m2. This should afford you very good control for different
lighting conditions. Contrast ratio remains stable across that adjustment
range as well.
Black
depth and contrast ratio are excellent thanks to the VA panel at 4128:1 after
calibration. Detail in darker scenes should not be lost as a result, and
shadow detail should be very good. Certainly a strong point of this panel.
There
is a specific 'movie' preset mode available for movies or video if you want
but it felt quite similar to our calibrated user mode, if a little cooler. Might be useful if you
need to have different settings or brightness for movies.
Good
pixel responsiveness which should still be able to handle fast moving scenes
in movies without issue. No overshoot issues which is pleasing as long as you
stick to the 'off' overdrive setting.
Pretty wide viewing angles thanks to VA panel
technology meaning several people could view the screen at once comfortable
and from a whole host of different angles. The vertical washing out of the
image is a little restrictive so you will want to ensure you can view the
screen head on. Thankfully unlike IPS panels there is no pale glow from an
angle on dark content, so this technology is more suited to movie viewing.
Non-existent ergonomic adjustments available
from the stand, so it's not the easiest to re-position for different viewing
positions. You can move it side to side easily enough on the desk as it's
quite light and has a thin profile, but the lack of tilt is a little
disappointing.
No
noticeable backlight leakage, and none from the edges which is good. This type
of leakage may prove an issue when watching movies where black borders are
present but it is not a problem here.
Basic
2x 7W integrated stereo speakers on this model which can handle some video
sounds without problem.
Decent
range of
hardware aspect ratio options with aspect, wide, 4:3 and 1:1 pixel mappings modes available which
should be fine for most uses.
Picture in picture (PiP) and Picture By Picture (PbP) are available with many
different configurations available.
The
screen does away with a lot of the video enhancement features you see on LCD
TV sets, as this is a desktop monitor primarily.
Conclusion
The first thing which strikes you about this
screen is of course its size! It's truly a massive screen and some might argue
that it's too big for every day desktop use. However, being so big does mean
that the 3840 x 2160 quad HD resolution works very comfortably and you don't
need to worry about OS and application scaling which is nice. The size and
resolution make multi-tasking very easy, and the wide range of MultiView PiP/PbP
options make split screening very practical. For gaming and movies the screen is
excellent, offering a size equivalent to most TV's and something which you can
comfortably use from a couple of metres away and still feel big, or from up
close giving you impressive immersion.
The VA panel performed very well overall, and we
were impressed particularly by a couple of areas, The contrast ratio was
excellent and clearly dark content and shadow detail is a strong point of this
screen. The response times were also impressive for this panel technology,
offering a decent gaming and movie experience for a VA panel. Default setup was
decent enough and it's not hard to tweak some settings to correct the colour
temperature. Unfortunately while the sRGB factory calibrated mode offered even
more accurate setup, the preset was locked at 100% brightness making it unusable
in practice. The uniformity correction mode worked well also which was pleasing,
but the setup of gamma and white point need correcting in that mode through
calibration. The VA panel offered pretty decent viewing angles as well, not as
good as IPS but the freedom from the pale glow on dark content that you get from
IPS was more beneficial on a screen this size. That lack of glow, the 4k
resolution and the high contrast ratio made it very enjoyable for movie viewing.
There were a couple of areas which were
disappointing. The lack of any ergonomic adjustments from the stand was
disappointing, but we suppose very comparable to modern TV's. The use of PWM for
backlight dimming was a shame as well. All in all we thought we would never get
used to a screen this size, but actually after a week or two of use it's very
useable. The screen is a very interesting choice for that all in one display,
which can be happily used as a decent desktop monitor and offer some very nice
LCD TV-style gaming and movie experience. The price is very attractive as well,
currently retailing in the UK at ~�689.99 (GBP). For a 4k screen so big, it's a
very nice option.
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Pros
Cons
Huge screen size and Quad HD
resolution very nice for a whole variety of uses
Very limited stand with no
ergonomic adjustments offered
Excellent black depth and
contrast ratio thanks to VA panel
PWM used for backlight dimming
Surprisingly good response
times
sRGB factory calibrated mode
locked at 100% brightness