It's not your average monitor,
but we thought it would be very interesting to take a look at Dell's new 21.5"
ST2220T display. What separates this from your average screen is that the
ST2220T uses optical touch screen technology to offer a nice cross over for
those wanting a tablet-like touch solution. Even if you ignore the touch screen
capabilities, the screen itself is still a very interesting model. It is a 21.5"
sized model using IPS panel technology. It has a unique design and a decent
range of options and extras. It even has a glossy panel coating which is bound
to attract some interest, as the traditional Dell anti-glare (AG) coating has
been a sore subject for some people with recent monitor releases. We wil review
the ST2220T in our normal way as a general monitor solution, and will of course
take a look at its touch-screen functionality as well. Let's start by taking a
look at the specs:
16.7m (6-bit + AFRC)
72% NTSC colour gamut (CCFL)
1920 x 1080
1000:1 and 50,000:1 DCR
DVI (HDCP), D-sub, HDMI
Glossy black bezel and stand
Tilt stand only. Optical touch screen
technology. 3x USB 2.0 downstream ports. Glossy panel coating
Dell ST2220T shown tilted to a low angle
The ST2202T is an attractive design in my opinion.
There is a glossy black bezel around the panel on all sides which is about 24mm
wide. At the bottom edge there is a wider patterned section which acts as the
stand and contains the stereo speakers. This is about 60mm thick at the widest
points (including the feet). The overall appearance is sleek and attractive and
it's a fairly unique design, a little like the
Asus MS246H we tested back in March 2010.
The screen coating for this model is a glossy
solution which does add a completely different feel to the screen as compared
with other popular Dell models. It helped give a sharp and vivid image I thought
and was very nice to look at. It did produce some extra reflections of course in
certain lighting conditions, and this could be an issue if you have a window or
light source behind you when you work. If you are using the touch-screen
capabilities then the coating will pick up finger print marks quite a lot, but
Dell do include a small cloth for wiping the screen at least. Screen coating is down to personal taste
of course but some people have found the aggressive AG (anti-glare) coating of
the recent Dell U series screens to be an issue.
views of the screen and stand. Click for larger versions
The back of the screen is also a nice glossy black
and everything looks smooth and well designed. There is a simple Dell logo on
the back and the whole unit looks very nice in my opinion. The materials were of
a high standard and build quality felt excellent.
The stand is a silver colour and has a non-slip
plastic base. This stand is used to control a very good range of tilt, from an
almost flat position against the desk, up to a vertical position. The images
below demonstrate this range of tilt. You can lay the screen flat on the desk as well
by folding the tilt stand away if you like. The screen goes to this flat level
since it is a touch screen and so some may want to operate it at that angle. The
operation of this tilt was very smooth and easy to use.
There is no height adjustment available from this
screen. Normally I would mark this as a negative if a stand did not offer a
height adjustment as I think it's a useful feature to obtain a comfortable
viewing position. However, it's a bit different due to the touch screen nature
and the ability to operate from an almost flat position. It's actually possible
to get a comfortable position for normal desktop use anyway which is good. Of
couse there's also no swivel or rotate function available from this screen.
view of the screen showing USB and headphone connections
The screen has a fairly thin side profile as well
as shown above. On the left hand edge are 3x USB 2.0 ports for easy connection
of external devices. This is great to see included as they can be very handy for
cameras, printers etc. It might have also been nice to see a couple on the back
of the screen with the video connections, as you may have some devices you want
to leave permanently connected and so want to keep the wires hidden out of the
way behind the screen. The popular Dell U series has additional ports on the
back as well as on the side, so a shame there weren't a couple more included
here I think. There is also a headphone connection on the left hand side if you
don't want to use the intergrated stereo speakers. Unlike some of the U series
of screens there is no card reader available here sadly.
One of the key selling points of the ST2220T is
its touch screen capability. We will test this later but I thought I'd mention a
bit about its capabilities here as well. The screen uses optical touch
technology for which you can use your finger, a stylus (min diameter of 7mm) or
any pointer device. The touch capabilities include mouse functionality (click,
drag, double-click and right click) along with supported Windows 7 multi-touch
gestures if you are using that operating system. Dell's spec states that there
is a typical touch response time of 15ms and that there is a
+/-2.5mm accuracy over 95% of the touchable area.
The screen also includes integrated 2W stereo
speakers which are housed in the bottom of the screen as shown above. These
should be more than adequate for general office noises and average use.
There is an audio input on the back as well to connect from your PC and the HDMI
input can also take sound as well as video. The headphone jack on the left hand
side of the screen can be used for discrete listening.
The back of the screen features a reasonable range
of interface options with DVI-D (HDCP supported), HDMI and D-sub available. It
may have been useful to see an additional HDMI or a DisplayPort connection here
as well, but there's a decent range nonetheless.
The back of the screen also features a useful
cable holder to tuck your cables nicely out of the way as shown above.
The OSD menu buttons are located on the right hand
edge of the screen and there are four there above the power button. The power
LED glows a subtle white colour during normal operation. The OSD menu buttons
are not labelled in any way. Pressing any of the buttons brings up the small
start menu in
the bottom right hand corner where there are indicators on the screen itself
telling you what each button does. It was easy to use and navigate, and very
intuitive as we had found with the Dell U series screens. With the buttons out
of sight on the edge of the screen it was perhaps a little more tricky to get
used to at first. There was quick access
(once you've pressed any button to bring up the small menu) to the preset modes
and brightness and contrast controls although these can be customised through
the 'personalize' menu when you get into the main sections.
The OSD menu has all the usual options you would
expect. The color settings menu gives access to the preset modes and there are
options for standard, multimedia, game, warm, cool and custom RGB.
The Dynamic contrast ratio control is located in
the display settings section but is only available when using the 'game' preset
mode. You will also notice that you can control the 'response time' setting here
as well which we will test later on in our
In terms of power consumption the manufacturers spec states
'typical' usage of 28W during operation, or up to 55W with USB active. In
standby, Dell say that the screen will use 1W of power.
We tested this ourselves and found that out of the
box the screen used a very low 28.0W of power which was as advertised by Dell. Once calibrated power consumption was 22.1W
(see calibration section)
since we had changed the OSD brightness control to 36% here. In standby the
power consumption was only 1.1W, so again, as advertised. The
screen remains pretty cool during operation, even after long periods of use and
hardly gives off any heat from the top of back. There is a very faint electronic
buzz if you press your ear against the screen but it's not something you'd
notice in normal use.
Accuracy, Black Depth and Contrast
The Panel and Backlighting Unit
The Dell ST2202T utilises an LG.Display e-IPS
LM215WF5-SLA1 panel and is capable of producing 16.7 million colours. The panel
itself actually uses a 6-bit colour depth with frame rate control (A-FRC) to
produce the 16.7m colours. This is different to regular 8-bit IPS matrices, but
this is likely a measure taken to achieve a lower price point for these modern
lower-cost displays. Studying detailed information from LG.Display's datasheet
confirms the panel is indeed 6-bit+AFRC.
The screen can offer a colour gamut covering
approximately 72% of the NTSC colour space as it uses standard gamut CCFL
backlighting. This colour space is approximately the same as the sRGB reference
but is less than modern wide gamut screens of course.
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.
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
X-rite i1 Pro spectrophotometer combined with
LaCie's Blue Eye Pro software suite. An X-rite i1 Display 2 colorimeter was
also used to verify the black point and contrast ratio since the i1 Pro 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 with the black triangle representing the
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 - we aim
for as high as possible. Any dynamic contrast ratio controls are turned off here
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
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 settings of the screen were as follows
Monitor OSD Option
Dell ST2220T - Default Factory Settings
Black Point (cd/m2)
The out of the box settings for the ST2220T were
actually pretty decent in most cases. The screen felt bright and colourful and
the glossy coating really helped bring out the detail and add something to the
'feel' of the panel. The colours felt even and fairly balanced although there
was a very slight tendency towards green. The screen was a bit too bright though
at its default 75% brightness setting, so this would need to be turned down for
most users in normal lighting conditions to get a comfortable setting.
The CIE digram confirms that the backlighting
offers a colour gamut which covers the sRGB reference well, extending a
little beyond that space along the blue > green edge but not by much. This does
confirm that this is a standard gamut model of course as wide gamut CCFL
backlighting would extend far beyond this reference. The default gamma setup was
good with only a 2% deviation from the 2.2 target. White point was also very
good being only 1% out from the 6500k at 6414k. The luminance was too high
though being recorded at 222
cd/m2. This did
give us a very good black depth though at 0.19 cd/m2, which produced
a 1169:1 static contrast which was excellent for an IPS panel. Colour accuracy
was also moderate with an average dE of 2.5. This did range up to 6.6 maximum
though in blue shades. Apart from the high brightness (which is easy to just
adjust through the OSD menu), this default performance was pretty good and
should be adequate for most regular users without the need for further
calibration. Obviously a colorimeter could help you obtain even better colour
accuracy, but at least the gamma and white point were well set up out of the
I also tested the screen at default settings after
switching to the 'Custom (RGB)' preset mode. This gives you access to individual
control over the red, green and blue channels for calibration procedures. I did
want to check whether this returned any more accurate results than the
'standard' preset. There was not really any difference in this preset. The
measurements were all within the same approximate percentages from the targets
as they had been before in the 'standard' mode. Colour accuracy was slightly
better on average now, with an average dE of 2.0 (instead of 2.5). However,
maximum dE was now 7.0 instead of 6.6. There's no real benefit in just switching
to this preset without further calibration steps, but it is useful to use if you
are doing anything more as the control over the RGB channels is useful.
I wanted to calibrate the screen in each of the
main preset modes to determine what was possible with optimum settings and
profiling. I 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 2 was used to validate
the black depth and contrast ratios due to lower end limitations of the i1 Pro
Dell ST2220T - Calibrated Settings
Monitor OSD Option
97, 91, 96
Custom RGB preset
Black Point (cd/m2)
I remained in the 'custom (RGB)' preset for this
process so that I could adjust the controls from the OSD menu. I followed
LaCie's calibration process through, adjusting the OSD settings in line with the
recommendations made in the process, and then letting the software carry out the
LUT adjustments at a graphics card level and create an
ICC profile. The screen does not feature a hardware LUT calibration option
so other than the OSD alterations, the rest of the process is carried out at a
graphics card level in profiling the screen.
The calibration was a success. The slight deviance
in gamma and white point was now corrected, and we had a much more comfortable
luminance of 120
cd/m2 now as we
had aimed for. We still had a very good black depth of 0.13 cd/m2 and
an excellent static contrast ratio of 925:1. Colour accuracy was also corrected
very nicely and we now had a dE average of 0.3 / maximum 1.0. LaCie would
classify colour fidelity as being excellent now.
You can use our settings and calibrated ICC
profile on your screen as well if you want. See
our ICC profile database for more information. I tested the screen with various colour gradients
which were very smooth and showed no sign of banding. There was only very slight
gradation as well so this was very positive.
I've plotted these measurements on the above
graphs in comparison with some of the other screens we have tested in a similar
size and market segment. Out of the box, default colour accuracy was very
similar to that of the other 21 - 23" e-IPS models we have tested. The
an average dE of 2.5 which was very similar to the 21.5"
Dell U2211H (2.3) and 23"
Dell U2311H (2.4). It was also very similar to the 23"
NEC EA232WMi (2.4),
NEC EA231WMi (2.7) and
Viewsonic VP2365wb (2.5)
displays. All these e-IPS panels
offer a pretty moderate default colour accuracy which would probably be adequate
for most casual users and pretty respectable when you consider the relatively low retail
Calibration with a colorimeter/spectrophotometer
can produce more accurate results of course and all these models are pretty
close in terms of dE performance. The ST2202T is ever so slightly behind at 0.3
whereas some of the models shown here are 0.2 average dE. Nothing you'd really
notice of course in practice. Don't forget that some of the models shown here
also offer further advantages when it comes to colour critical work.
Professional grade monitors like the NEC PA series also offer other high end
features which separate them from some of these other models, including extended
internal processing, 3D LUT's and hardware calibration. These comparisons are
based on a small selection of tests, so it should be remembered that other
factors do come into play when you start talking about professional use. For
further information and tests of a high end professional grade screen with
hardware LUT calibration, you may want to have a read of our
NEC SpectraView Reference 271 review.
I've included a comparison of the black point and
contrast ratio above as well. The ST2220T performed very admirably here, being
one of the
best of the IPS screens in fact. With a very low 0.13
point, calibrated static contrast ratio was 925:1 which was excellent and only a little
short of the advertised 1000:1. We'd actually achieved a little higher than this
at default settings (see
next section) but these results above factor in a
post-calibration performance after grey scale, gamma, white point (etc)
correction. The IPS based
NEC EA232WMi was slightly better at 933:1, the TN Film based
BenQ XL2410T was actually a little better at 996:1, and the
AMVA panel offered a fantastic contrast ratio of 2995:1. A very good performance
from the Dell ST2220T here nevertheless.
I 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 the case in practice. In most monitors the
brightness control in the OSD menu controls the intensity of the backlight
unit, and so as you reduce this control you reduce the luminance. Black depth
should also reduce at the same time, and hopefully maintain a stable contrast
ratio across the range of adjustments. Where the brightness control does not
change the backlight intensity it can have a significant impact on the
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 2 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.
Black Point (cd/m2)
Luminance Adjustment Range = 198 cd/m2
Point Adjustment Range = 0.17
Contrast Ratio = 1167:1
The brightness control afforded us a decent enough
range of adjustments to the luminance of the screen. At the top end, a 100%
setting returned us a luminance of 268 cd/m2
which is actually slightly higher even than the specified 250 cd/m2
from the manufacturer. This could be adjusted down to around 70 cd/m2
at a 0% setting which was decent enough. A setting of around 25% should return
you a luminance of ~120 cd/m2 which is recommended for LCD screens in
normal lighting conditions. That assumes no other settings are changed of
course, but should give you a decent starting point and a more comfortable
setting to save your eyes.
Black depth was excellent
across the adjustments, ranging from 0.23 cd/m2 down to
0.06 cd/m2. Overall the static contrast ratio was very stable and
there was an excellent average contrast ratio of 1167:1. I have plotted these
results on the graph below.
The Dell ST2220T features a dynamic contrast
ratio (DCR) control, which boasts a spec of 50,000:1
Dynamic contrast ratio involves controlling the
backlight of the screen automatically, depending on the content shown on the
screen. In bright images, the backlight is increased, and in darker images, it
is descreased. For this test I would use the colorimeter to record the
luminance and black depths at the two extremes. Max brightness would be
recorded on an all white screen once the DCR has caught up. Black depth would
be recorded on an all black screen.
The DCR feature is only available when you enter
the 'game' preset but is not available in the 'multimedia' mode for some
reason. I've never really found that Dell's DCR's do much in practice to be
honest and have been a bit underwhelmed by their performance. Here is sadly no
exception. When you enter the game mode and turn DCR on the brightness control
is locked from the OSD menu. I carried out our usual tests, and even switching
between a fully black and fully white image didn't seem to show any real
variance in the backlight intensity. This DCR didn't seem to function at all
as far as I could tell.
Game preset mode
Max luminance (cd/m2)
Min Black Point (cd/m2)
Max Dynamic Contrast Ratio
The dynamic contrast ratio control didn't really
work at all. We were left with a contrast ratio which was only really the same
as our default static contrast ratio figure we had
measured before. To be
honest this 50,000:1 figure is exagerated massively anyway. Even if the DCR
technolgy could control the full range of the backlight properly, you would only
have a maximum luminance of around 268
cd/m2, and a
minimum black point of 0.06 cd/m2. You can see this from our
tests above. This would only give you a maximum DCR of 4467:1 anyway so a
long way off the advertised figure. If we took Dell's maximum brightness spec of
250 cd/m2, you would need a black point of 0.005 cd/m2 to
achieve the 50,000:1 figure, something which clearly this panel is
not capable of, even at 0% intensity.
angles shown from front and sides, and from above and below. Click for
Viewing angles of the ST2202T are very good,
as you would expect from a screen based on an e-IPS panel. Horizontally there
are very wide fields of view with a small contrast shift only really becoming
noticeable from a fairly wide angle of about 45°. Vertically, the contrast shift
was a little more pronounced but the fields of view were still very good. The
panel is free from any off-centre contrast shift which you see from VA matrices,
and this is why IPS technology is so highly regarded in the colour enthusiast
and professional space. It is also free of the very noticeable contrast and
colour tone shifts you see from TN Film panels vertically. On a black image
there is a slight purple hue when viewed from some wide angles, and from others,
a moderate white glow. The
glossy panel coating does reflect light quite a lot though so you do have to be
careful when viewing from an angle not to catch windows or lamps reflecting from
Measurements of the screens 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 the X-rite
i1 Display 2 colorimeter. The above uniformity diagram shows the difference, as
a percentage, between the luminance recorded at each point on the screen, as
compared with the reference point of a calibrated 120 cd/m2. This is
the desired level of luminance for an LCD screen in normal lighting conditions,
and the below shows the variance in the luminance across the screen
compared with this 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 uniformity of the panel was moderate as a
whole. The luminance was a little darker towards all four edges, particularly
along the right and left hand sides. Here the luminance ranged down to 99
cd/m2 in the worst cases which was not
too severe. 65% of the screen was
within 15% deviance from the target at a central point which was ok but not
perfect. It was very hard to notice this variation in practice but if you viewed
an all grey background in a darkened room, you could just about pick out a
slightly darker right hand side, but this was not easy to spot. I don't think
the luminance uniformity should cause any real problems to a normal user.
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.
Uniformity of the backlight was very good in this test. There was very minimal
leakage at all, apart from a slight amount in the top left hand corner and a
little along the lower left hand edge. You can notice this using the naked eye
when viewing an all black background in a darkened room, but in practice you are
unlikely to see any real issue her I don't think.
General and Office Applications
Normally I would rate a 20 - 22" sized screen down
a little in terms of its use for office applications, but this would normally be
down to its 'small' (by todays standards) 1680 x 1050 resolution. Thankfully in
the case of the ST2202T, like the Dell U2211H, the panel used offers a full 1920 x 1080 resolution.
This is the same as many popular 23 - 24" screens and it's good to see a high
resolution on a smaller screen. The pixel pitch is obviously a little smaller
than the larger screens since you are squashing the full resolution into a
smaller screen diagonal. However, at 0.248mm I still felt it was comfortable for
prolonged office use without text being too small. I'd found the 0.233mm pixel
pitch on the
Dell U2711 (2560 x 1440 resolution / 27" screen size) to be a little too
small for my personal preference, but the ST2202T was not as severe. This 1080
resolution is suitable for some good side by side working which I think is
always handy for office use.
The luminance of the screen was too high at
default settings but not too bad. You are easily able to adjust the brightness control to reach a
comfortable luminance for varying lighting conditions. A brightness setting of
25 - 30% should give you a luminance of around 120
cd/m2, and you
can get lower should you desire, down to a decent 70 cd/m2.
There's no preset mode for 'text' or 'internet' here, so you will need to
calibrate one of your preset modes to a suitable luminance if you are using a
lot of office applications. It should be noted that the brightness/contrast
setting applies to all preset modes so you cannot save a setting individually
for any given preset. I personally think that ambient light sensors and
dynamic backlighting control can be useful for office work, but there isn't one
available here sadly.
The screens ergonomics are limited here but do afford you a decent
range of tilt which is easy to use and should allow
you to get a position you want. For office use, it is a shame not to see height,
swivel or rotate functions available though. The 3x USB 2.0 ports on the left
hand edge are useful as well for connecting cameras, printers etc. A card reader
might have been a nice added extra as well like some of the U series screens.
Both the DVI and VGA interfaces presented a clear
and sharp image and there was very little difference noticeable to be honest.
The DVI digital interface had a very slight edge so is obviously the preference
if you can use it. The glossy screen coating does add a nice 'feel' to the
screen and white text backgrounds appear clean and crisp, and free from any
'dirty' feel that some people complain about with aggressive AG coating on
panels. It does however occasionally present an issue with reflections in some
lighting conditions which you need to be careful of.
Responsiveness and Gaming
Before we get into the side by side screen
comparisons I first wanted to have a look at the 'overdrive'
feature Dell have built into this monitor. This option is available via the
'display settings' section of the OSD menu as shown above. Dell's spec for the
ST2220T states that the screen has an 8ms G2G response time with overdrive
activated. It also states a 14ms G2G figure when overdrive has been switched
off, although if the function is truly switching off the
Response Time Compensation (RTC) impulse then this perhaps should read as a
14ms ISO measurement instead, which would also be in keeping with modern e-IPS
panels without RTC (e.g. NEC EA232WMi = 14ms ISO response time). We tested the
screen using the PixPerAn tool with overdrive enabled and disabled and the
results are captured below.
The screen was tested using the chase
test in PixPerAn, a good bit of software for trying to quantify differences in
real terms responsiveness between monitors. As a reminder, a series of pictures
are taken on the highest shutter speed and compared. The images below show the
best case example on the left hand side, and the worst case example on the right
hand side. This should only be used as a rough guide to comparative
responsiveness but is handy as a way of keeping a constant test of each screen.
14ms LG.Display e-IPS (overdrive OFF)
G2G LG.Display e-IPS (overdrive ON)
As you can see there is a defined improvement in
responsiveness when you enable the overdrive function on this screen. To be fair, even
without this activated the moving car does not show any obvious ghosting images,
but does show some fairly obvious motion blur. The camera captured a fairly
noticeable trail image, even in the best case example, and this is in keeping
with the non-overdriven e-IPS panels in screens like the NEC EA232WMi and
ViewSonic VP2365wb. Once the overdrive is turned on the motion blur is reduced
quite nicely although there is a very slight pale halo introduced as a result of
the RTC impulse and some slight overshoot. This is just about detectable in the
best case image above but a little bit more apparent in the worst case example.
For gaming, I would certainly recommend having this function turned on as it
does help improve responsiveness and there are very few artefacts to worry about
14ms LG.Display e-IPS (overdrive OFF)
14ms LG.Display e-IPS (W-LED)
14ms LG.Display e-IPS
Overdrive = Off: The ST2220T performs
almost identically to the NEC and ViewSonic models here, neither of which use
RTC to boost pixel responsiveness. Those two models are rated with a 14ms ISO
(black > white > black) response time and so this does back up the
the spec of the Dell without overdrive enabled should really be 14ms ISO, and
not 14ms grey to grey. Regardless, the screen behaves like these other models with the
G2G LG.Display e-IPS (overdrive ON)
23" 8ms G2G LG.Display e-IPS
G2G LG.Display H-IPS
24" 5ms G2G LG.Display e-IPS
Overdrive = On: With the overdrive function
enabled the motion blur is reduced nicely and the responsiveness is better. It's
not actually a drastic change when you switch between the two, but the
improvement is there. The ST2220T performs quite similarly to the other Dell
models shown here. The 23" U2311H has a slightly less pronounced blur, but there
is slightly more of a white trail evident. The RTC impulse is a little bit more
aggressive on the U2311H model which gives you this result. The 24" U2410 is
very slightly faster than the ST2220T but nothing really that you'd ever notice
in practice, and the 24" HP ZR24W is very similar again. I'd say that the
ST2220T offers a very comparable performance to all three of these competing
models really in normal use.
G2G LG.Display e-IPS (overdrive ON)
23.6" 2ms G2G CMO TN Film (120Hz)
22" 3ms G2G Samsung TN Film + 120Hz
I've also included a comparison above against two
gamer-orientated screens, both featuring heavily overdriven TN Film panels, and
120Hz technology. The pixel responsiveness of both of these is a little ahead
of the ST2220T as you will probably expect and the 120Hz frequency allows for
improved 120fps frame rates and the support of 3D content as well. The BenQ
XL2410T does show some rather noticeable RTC overshoot in the form of dark
trails behind the moving image (speech bubble and head) which is unfortunate,
and a sign that the RTC impulse is too aggressive. The Samsung 2233RZ remains
our champion in this test.
The Dell ST2220T should be perfectly adequate for
but those wanting to play fast FPS may still want to look elsewhere, perhaps at some
of the modern 120Hz TN Film models with super fast response times and support for 120fps frame rates and 3D content. If you do buy the Dell
ST2220T then I would certainly recommend making use of the overdrive function
which improves pixel responsiveness nicely.
Apsect Ratio Control - The ST2220T supports
aspect ratio control options through the OSD 'display settings' menu. There are only options for 'full' and '4:3' though, so
any other aspect ratios and 1:1 pixel mapping are not catered for via the
Preset Modes - There is a gaming preset
mode available for those who want to set up a preset based on their
requirements. The dynamic contrast ratio is only available when using this mode
although didn't seem to work at all.
The preset was a little more blue as well than our calibrated custom (RGB)
As usual I tested the
screen in clone mode with a CRT to determine the level of
input lag. This is
something which can put off some gamers and is a delay between graphics card and
monitor output. By hooking up a CRT you can show that the LCD lags behind
somewhat, which can affect users in some situations where they rely on the
screen image being as fast as their inputs (e.g. fast FPS shooting games).
Often, input lag is very low and probably wouldn't represent too much of a
problem in real terms.
The input lag of the ST2220T
was pretty good really, with an average delay of only 16.3ms. This ranged up to
20ms in the worst cases which again was not bad. This puts it on par with the
Dell U2211H and only slightly behind the U2311H and U2410 in fact. With this
level of input lag, users shouldn't find it a problem for most gaming to be
Movies and Video
The following summarises the screens performance
in video applications:
21.5" screen size makes it a reasonable size for viewing movies, but fairly
small by todays standards. With the availability of 23-24" screens now, you
might find something bigger more suitable
aspect ratio is more suited to videos than 16:10 format screens, leaving
smaller borders on DVD's and wide screen content.
x 1080 resolution can support true 1080 HD resolution content. Good to see a
full 1080 resolution being used on a 21.5" screen
Digital interfaces support HDCP for any encrypted and protected content
Fairly decent interface options available with 1x DVI, 1x HDMI and 1x D-sub.
Might have been good to see DisplayPort available as well
Black depth and contrast ratio are excellent and some of the best we have seen
from an IPS panel. Detail in darker scenes should not be lost
Dynamic contrast ratio is available but doesn't really work at all sadly.
Multimedia preset mode is available. This looked fairly similar to our
calibrated custom profile. might be useful to some
pixel responsiveness meaning fast moving images should be fine. I would
recommend having overdrive enabled.
backlight bleed along the top and bottom edges which is great, as this could
prove distracting in movies, especially where black borders are present. Some
slight leakage from the top left hand corner and left hand edge, but nothing
too severe and shouldn't present any real problems in movie viewing.
viewing angles thanks to IPS panel technology making it suitable for viewing
from different positions and for multiple viewers without issue
Decent tilt adjustment available but otherwise very limited. Might present a
problem when trying to find a comfortable position for the screen,
particularly with multiple viewers..
Integrated stereo speakers might be useful for 'light' sound and general use.
The headphone socket is also useful for quieter viewing.
Glossy panel coating may present problems with reflections depending on your
viewing position and lighting conditions. Keep it away from a window as they
are particularly noticeable.
Touch Screen Capability
To take advantage of the touch screen capabilities
of the ST2202T the screen must be connected to your PC's USB port using the
provided cable. This connects to the upstream interface on the back of the
monitor, and is also used to allow the 3x USB 2.0 downstream ports on the side
function. There is a driver package supplied on the CD-rom or available from
Dell's website which must be installed first. There is only support for Windows
Vista and Windows 7 officially, and I could find no information on using this
function with Windows XP. Mac OS is also not officially supported at this time.
The touch screen allows you to interact with
the computer in a similar way to a mouse as follows:
the screen once for a single mouse click.
the screen twice in quick succession for a double mouse click.
down and then move your finger to drag an object.
and hold for a right mouse click.
select a menu option, touch down on the menu, then move your finger to the
required option, then lift your finger to select the option. Alternatively,
tap the menu, then tap the option required as you do with a mouse.
The touch screen does not
require much pressure to sense a touch either and for best results you have to
point at roughly right angles to the screen and keep the rest of your hand clear
of the glass. You can use your finger or a stylus which offers a little bit more
accuracy. I found the finger touch to be perfectly useable though once you've
got accustomed to the 'aim' and have used it for a few minutes. There was only
minimal lag as well which was good, nothing which should cause you problems in
practice I don't think. Dell rate this lag at 15ms incidentally.
I took the above video which shows the touch
screen in operation in a series of functions as explained below. This was
connected to a Windows 7 machine.
Simple one press activation - you will spot
there is a small target and 'splash' when you press the screen showing where
you have touched
Dragging and moving the control panel window
around. This is easy to do and you can spot the slight lag as you do this, but
it's not too bad I don't think.
Double clicking to make the control panel
window full size and then small again. This is very easy to do and the screen
Dragging the control panel window again off
the screen which activates the Win7 split screen viewing automatically
I then zoomed the camera in to show the
right click function. You have to press and hold the screen for about 1.5
seconds. A circle then appears and goes around your touch-point. When you
release the screen the right click menu appears. This is one area which is of
course a little more cumbersome than using a mouse as you have the added press
and hold in there. When you start trying to copy and paste it becomes quite a
drawn out process with all these holds.
I then clicked into the address bar (after
missing the first press!). On the left hand edge of the screen a small app
appears. When you press this, it pops out a little way allowing you to click
it. This in turn flashes a touch screen keyboard into view. This is easy
enough to use and offers a full QWERTY layout
I then demonstrate the dragging and
scrolling in an internet window. First I use the scroll bar and drag that up
and down which operates well. I then just press, hold and scroll the same
webpage using the touch screen functionality which is good.
Lastly I again drag the control panel window
around for good measure.
I then did a shorter video which shows you the
multi-touch functionality of Windows 7. You can, with two fingers, pinch and pull the screen
to zoom in and out, very much like you can on an Apple iPhone / iPad. You can
also click and then highlight text, but this is a little more tricky to get used
to and certainly not as easy as using a mouse.
I really enjoyed
using the Dell ST2220T actually, as it was something a little different to other
screens we have tested. If I ignore the touch-screen capabilities for now, the
performance of the screen itself was excellent I thought. Factory set up of
gamma and colour temperature were very good and colour accuracy was decent
enough for most casual users. The black depth and contrast ratio were excellent
as well for an IPS panel which was a great result. Once calibrated the
performance was of course even better. I had no real complaints about the
viewing angles or uniformity either really. Yes, there were some slight
variations in luminance uniformity along the sides, but nothing too severe and
the screen was pretty much free from any backlight bleed. The response time and
input lag was also very good and on par with other modern fast IPS panels in this
liked the sleek design of the screen as well and it looked very nice sat on the
desk. While it is a bit of a shame to be missing height adjustment, I didn't
really find it too much of a problem in my personal use, and the tilt range was
excellent and easy to use. The glossy panel coating did add to the
'feel' of the screen and appearance of the image which I liked. Unfortunately it
was a little too reflective in some conditions. The touch-screen support was
also a nice feature and fun and easy to use.
performance of the monitor itself is very comparable to Dell's popular U2211H
model, just with a few significant changes like the different design, integrated
speakers, added touch-screen support and a glossy panel coating. I suppose many
people would not have the need for the touch screen functionality day to day,
but the screen should not be dismissed as just a standalone monitor I don't
think. The ST2220T does cost a little bit more, being priced at ~£270 GBP at the
time of writing, compared with the £220 of the U2211H. However, the extra £50
for the additional features is very reasonable I think. As a touch screen
monitor it is a very nice solution I think, but even if you forget it has that
support the ST2220T is a very nice 21.5" IPS screen which is well worth looking
Good default setup and great
black depth / contrast ratio
Disfunctional dynamic contrast
Fast response time and low
Although offering a decent
tilt range, no heigh adjustment from the stand
Glossy screen coating improves
the feel of the screen, and touch screen support is very useable
Reflections potentially an
issue due to glossy screen coating