Flagship Smartphone Display Technology Shoot-Out
Apple iPhone 5 – Samsung
Galaxy S III – Apple iPhone 4
Dr. Raymond M. Soneira
President, DisplayMate Technologies Corporation
Copyright © 1990-2012 by DisplayMate
Technologies Corporation. All Rights Reserved.
This article, or any part
thereof, may not be copied, reproduced, mirrored, distributed or incorporated
into any other work without
the prior written permission of DisplayMate Technologies Corporation
Introduction
The iPhone 5 has been the most anticipated mobile device of 2012
together with its cousin the iPad Mini, which we expect to be seeing shortly.
Apple has made displays their most prominent marketing feature because it
determines the quality of the visual experience for everything on a Smartphone
or Tablet – including Apps, web content, photos, videos, and its camera. The
Retina Displays on the iPhone 4 and the new iPad were significant advancements
– not just in sharpness but in picture quality and color accuracy, which is
what provides the display’s real Wow factor.
So how good is the display on the iPhone 5? There has been an incredible
increase in competition since the introduction of the iPhone 4 in 2010:
displays have gotten a lot bigger (possibly too big), more manufacturers are
using similar high-end IPS LCDs like Apple, and many Smartphones are using the
latest OLED displays manufactured by Samsung – with the Samsung Galaxy S III as
the premier Flagship product.
First we’ll compare the display on the iPhone 5 to the iPhone 4 to see
if it is indeed much better, which could be an important factor for those
considering whether to upgrade. Then we’ll compare the iPhone 5 to its primary
competitor, the Samsung Galaxy S III, and we’ll also see how well it compares
to the outstanding display on the new iPad.
The Shoot-Out
To compare the performance of the Apple iPhone 5 and Samsung Galaxy S III
we ran our in-depth series of Mobile
Display Technology Shoot-Out tests on them. We also included the iPhone 4 in order to determine how the display on the
iPhone 5 has been improved. We take display quality very seriously and provide
in-depth objective analysis side-by-side comparisons based on detailed
laboratory measurements and extensive viewing tests with both test patterns and
test images. To see how far Smartphones have progressed in just two years see our
2010 Smartphone
Display Shoot-Out, and for a real history lesson see our original 2006 Smartphone
Display Shoot-Out.
Results Highlights
In this Results section we provide Highlights of the
comprehensive Lab measurements and extensive side-by-side visual comparisons
using test photos, test images and test patterns that are presented in later
sections. The Comparison Table in the
following section summarizes the lab measurements in the following categories:
Screen Reflections, Brightness and Contrast, Colors and Intensities, Viewing Angles, Display Power Consumption, Running Time on Battery. You can also
skip the Highlights and go directly to the Conclusions.
Comparing the Displays on the iPhone 4 and iPhone
5:
The display on the iPhone 5 is a significant
improvement over the display on the iPhone 4. Apple has uncharacteristically
understated how much better the display is on the iPhone 5 – something that
could be an important factor for those considering whether to upgrade. In every category that
we measure (except Brightness Decrease with Viewing Angle), the performance of
the iPhone 5 display has improved over the iPhone 4, sometimes by a bit and
sometimes by a lot. Everyone knows about the 18 percent increase in screen area, but
here are 3 major display enhancements on the iPhone 5 that we will discuss in
detail below:
Screen
Reflectance on the iPhone 5 has
decreased substantially – the iPhone 4 has 52 percent brighter reflections than
the iPhone 5. This means you won’t be distracted as much by reflections that
appear on the screen. The iPhone 5 has among the lowest Reflectance values we
have ever measured on a Mobile device.
The
iPhone 5 has the highest Contrast Rating for High Ambient Light for any Mobile device we have ever
tested, and it’s 57 percent higher than the iPhone 4. This means screen
readability in bright ambient lighting has improved substantially – both the
image colors and contrast won’t appear as washed out outdoors as on other
Smartphones, including the iPhone 4.
The color quality and color accuracy have improved
substantially. The iPhone 5 received a Color Gamut and Factory Display
Calibration upgrade similar to the new iPad. While it’s not quite as
accurate as the Excellent calibration on the new iPad, it is still Very Good
and probably more accurate than any consumer display you own (including your
HDTV), unless you have a new iPad.
The iPhone 5 Display:
It’s
still a Retina Display with 326 Pixels Per Inch PPI and with a Resolution of
1136x640 pixels. We were hoping for 1280x720, which is Standard High Definition
HD, but presumably that will be for the iPhone 6. That’s not a disappointment,
just a wish list… Based on our extensive Lab measurements the iPhone 5 has a
true state-of-the-art display – it’s not perfect and there is plenty of room
for improvements (and competitors) but it’s the best Smartphone display we have
tested to date.
We’ll
examine the iPhone 5 display in detail below, but here are the Highlights: it
is the Brightest Smartphone we have tested in the Shoot-Out series, it has one
of the lowest screen Reflectance values we have ever measured, it has the
highest Contrast
Rating for High Ambient Light for any Mobile device we have ever tested, and it’s Color
Gamut and Factory Calibration are second only to the new iPad. What are the
downsides? The White Point is still somewhat too blue like most Smartphones,
and at Maximum Brightness it has a shorter Running Time than the iPhone 4,
which is not surprising since it has a larger screen and a larger Color Gamut
but roughly the same capacity battery.
The Galaxy S III Display:
Samsung
also features their displays when marketing Smartphones, but they have taken a
very different approach – they are using Samsung’s own OLED displays, a new and
rapidly evolving display technology that is very different from LCDs, with its
own particular set of advantages and disadvantages. It’s a new technology that
attracts early adopters, but it has not yet been refined to the same degree as
LCDs, which have been mainstream for over 20 years. It’s clear that OLEDs in
the near future will do to LCDs what LCDs did to CRTs, but we are not there
yet… So OLEDs have a number of rough spots that show up clearly in our
objective Lab testing.
We’ll
examine the OLED Galaxy S III display in detail below, but here are the
Highlights: the Brightness is about half of the iPhone 5 due to power limits
from the lower power efficiency of OLEDs and concerns regarding premature OLED
aging. The Color Gamut is not only much larger than the Standard Color Gamut,
which leads to distorted and exaggerated colors, but the Color Gamut is quite
lopsided, with Green being a lot more saturated than Red or Blue, which adds a
Green color caste to many images. Samsung has not bothered to correct or
calibrate their display colors to bring them into closer agreement with the
Standard sRGB / Rec.709 Color Gamut, so many images appear over saturated and
gaudy. Running Time on battery is less than the iPhone 5 due to the lower power
efficiency of OLEDs, even given that the Galaxy S III has a much larger battery
capacity and much lower Brightness.
The
Galaxy S III has a PenTile OLED display, which has only half of the number of
Red and Blue sub-pixels as in standard RGB displays, like those on the iPhones.
The eye’s resolution for color image detail is lower, so this works well for
photographic and video image content, but NOT for computer generated colored
text and fine graphics because it produces visible pixelation, moiré, and other
very visible artifacts, so a PenTile display is not as sharp as its pixel
Resolution and PPI would indicate. PenTile technology does have advantages in
manufacturing, aging and cost. For a more detailed analysis see our Samsung
Galaxy S OLED Display Technology Shoot-Out.
Color Gamut and Color Accuracy:
While
the display Pixels Per Inch PPI and pixel Resolution seem to get most of the
attention, it is the display’s Color Gamut together with the Factory Display
Calibration that play the most important role in determining the Wow factor and
true picture quality and color accuracy of a display. The Color Gamut is the
range of colors that a display can produce. If you want to see accurate colors
in photos, videos, and all standard consumer content the display needs to closely
match the Standard Color Gamut that was used to produce the content, which is
called sRGB / Rec.709. A display with a larger Color Gamut cannot show colors
that are not in the original content - it just exaggerates and distorts the
colors. Most of the recent generation LCD Smartphones have Color Gamuts around
60 percent of the Standard Gamut, which produces somewhat subdued colors. The
iPhone 4 has a 64 percent Color Gamut, but the new iPad pulled way ahead and
has a virtually perfect 99 percent of the Standard Color Gamut. The iPhone 5
has an almost identical Color Gamut to the new iPad and the Viewing Tests
confirm its excellent color accuracy.
While
Apple has clearly made a big effort in getting the Color Gamut very accurate
for the new iPad and iPhone 5, Samsung has not bothered to calibrate the Color
Gamut on any of its OLED displays, so they are wildly inaccurate and produce
inaccurate and over saturated colors. The Color Gamut is not only much larger
than the Standard Color Gamut, which leads to distorted and exaggerated colors,
but its Color Gamut is quite lopsided, with Green being a lot more saturated
than either Red or Blue, which adds a Green color caste to many images. The
Viewing Tests bear this out. Compare the Color Gamuts in this Figure and below.
Viewing Tests:
Using
our extensive library of challenging test and calibration photos, we compared
the Smartphones to a calibrated professional studio monitor and to the new
iPad, which has a virtually perfect Factory Calibration and Color Gamut. As
expected from the Lab measurements, the iPhone 5 produced beautiful picture
quality, much better than the iPhone 4, which has a much smaller Color Gamut,
and comparable to the new iPad, but with slightly greater image contrast and
color saturation due to its steeper Intensity Scale and larger Gamma. See these Color Gamut and Intensity Scale figures for
details and explanations.
But
what really impressed me was that all of the photos and their colors on both
the iPhone 5 and new iPad appeared virtually identical. You never see that in
any consumer product unless it has been professionally calibrated (with varying
degrees of success). So if you switch devices or share photos and content with
friends and family you know that they will be seeing exactly what you are
seeing…
The
Color Gamut of the Galaxy S III is significantly larger than the Standard Color
Gamut so it produces over saturated colors that can appear comic book like and
gaudy in some instances. Photos appear with way too much color. It’s similar to
turning the Color Control way up on your HDTV. If the images have relatively
low color saturation to begin with then they look more vibrant but not
objectionable. However, if the images have vibrant colors to begin with, like a
fire engine, then the images can be visually painful to look at. When compared
side-by-side to the accurately calibrated iPhone 5 and new iPad, the Galaxy S
III looked gaudy.
Screen Reflectance and
High Ambient Lighting:
The
screens on almost all Smartphones and Tablets are mirrors good enough to use
for personal grooming. Even in moderate ambient lighting the image contrast and
colors can noticeably degrade from ambient light reflected by the screen,
including objects like your face and any bright lighting behind you. So low
Reflectance is very important in determining real world picture quality. This article
has screen shots of how images degrade in bright ambient lighting. The iPhone 5
has the highest Contrast Rating for High Ambient Light for any Mobile device we have ever tested.
Because of its low screen Brightness the Galaxy S III has a much poorer
Contrast Rating and screen visibility in bright ambient light.
The Rumored Apple Television?
If you have ever walked into Walmart or Best Buy and
compared the multitude of HDTVs you know that every single TV produces a
different looking picture (and they are all inaccurate). So why should Apple
introduce its own Apple Television with an actual TV screen as opposed to just
relying on an Apple TV streaming box connected to any TV? Because existing TVs
are poorly calibrated and produce inaccurate and inconsistent colors and images
that will be poor matches to Apple's own accurately calibrated iPhones and
iPads. The best solution will be for Apple to manufacture its own Television with
the same accurate calibration as its other displays. Consumers will love the
fact that everything including their personal photos, TV shows, movies, and
videos will all look exactly the same on all Apple devices.
Conclusions: An Impressive iPhone 5 Display…
Smartphone displays are continuing their rapid
evolution in performance. Apple has again taken the lead in methodical
refinements and factory calibration that are necessary to produce accurate very
high picture quality. Based on our extensive Lab measurements the iPhone 5 has
a true state-of-the-art accurate display – it’s not perfect and there is plenty
of room for improvements (and competitors) but it is the best Smartphone
display we have seen to date based on extensive Lab measurements and viewing
tests. In particular it is a significant improvement over the display in the
iPhone 4 with much lower screen Reflections, much higher image contrast and
screen readability in high ambient lighting (the highest we have ever
measured), and a significantly improved and accurate Color Gamut and Factory
Calibration that delivers very accurate colors and very good picture quality.
While it’s
not quite as accurate as the new iPad, it is still probably more accurate than
any consumer display you own (including your HDTV), unless you have a new iPad.
The
display on the Samsung Galaxy S III uses OLED technology. It’s a new technology
that has not yet been refined to the same degree as LCDs, particularly the IPS
LCDs on the iPhones, so it doesn’t objectively test or perform as well as the
iPhone 5. But OLEDs have been evolving and improving very rapidly as shown in
our OLED
Display Technology Shoot-Out so it has a very promising future. Here are
the biggest issues we found in our extensive Lab measurements and viewing tests
of the Galaxy S III: the Brightness is about half of the iPhone 5 due to power
constraints resulting from the lower OLED power efficiency and concerns
regarding premature OLED aging. As a result the image contrast and screen
readability in high ambient lighting is much poorer than the iPhone 5. The
Color Gamut is not only much larger than the Standard Color Gamut, which leads
to distorted and exaggerated colors, but the Gamut is quite lopsided, with
Green being a lot more saturated than either Red or Blue, which adds a Green
color caste to many images. And for some reason Samsung has not bothered to
calibrate the Color Gamut on any of its OLED displays, so they are wildly inaccurate
and produce inaccurate and over saturated colors.
Suggestions
for Apple:
Keep up the good work in improving picture quality through accurate display
calibration! To produce a better display please don’t make the White Point
Color Temperature so blue – it’s the only significant calibration flaw and it
gives some images a bit of a cold bluish caste. The Intensity Scale on the
iPhone 5 should be changed to match the excellent calibration of the new iPad.
Finally, consumers have varying tastes in color saturation and image contrast –
why not give displays the equivalent of an audio equalizer to let everyone
adjust the display to their own personal visual preferences?
Suggestions
for Samsung:
Keep up the good work in improving OLED displays! To produce a better OLED
Smartphone, use a smaller size display (that uses less power), add a bigger
battery to increase the screen Brightness and running time on battery, and most
all – please calibrate the display so that its Color Gamut matches the Standard
Color Gamut and the display delivers accurate rather than distorted,
exaggerated, and gaudy colors!
Suggestions
for all manufacturers: There is still plenty of Room for Improvement. See the new iPad
Shoot-Out Conclusion for a discussion of the many improvements that are
needed for the next generation of Smartphone and Tablet displays.
DisplayMate Display Optimization Technology
All
Smartphone and Tablets displays can be significantly improved using
DisplayMate’s advanced scientific analysis and mathematical display modeling
and optimization of the display hardware, factory calibration, and driver
parameters. We help manufacturers with expert display procurement and quality
control so they don’t make mistakes similar to those that are exposed in our
Display Technology Shoot-Out series. We can also improve the performance of any
specified set of display parameters. This article is a lite version of our
intensive scientific analysis – before the benefits of our DisplayMate Display Optimization
Technology, which can correct or improve all of these issues. If you are a
display or product manufacturer and want to significantly improve display
performance for a competitive advantage then Contact DisplayMate Technologies.
Display Shoot-Out Comparison Table
Below we
compare the displays on the Apple iPhone 5 and Samsung Galaxy S III together with the iPhone 4 based
on objective measurement data and criteria. Note that the tested Smartphones
were purchased independently by DisplayMate Technologies through standard
retail channels.
For additional
background and information see the iPad Retina Display
Technology Shoot-Out article that compares and analyzes the new iPad, the iPad 2, and iPhone 4,
and the Samsung
Galaxy S OLED Display Technology Shoot-Out that compares and analyzes the
evolution of the OLED displays on the Galaxy S I, II, and III and
compares and analyzes PenTile displays compared to standard RGB displays.
|
Categories
|
Apple
iPhone 4
|
Apple
iPhone 5
|
Samsung
Galaxy S III
|
Comments
|
|
Display Technology
|
3.5 inch
IPS LCD
|
4.0 inch
IPS LCD
|
4.8 inch
PenTile
OLED
|
Liquid Crystal Display with In Plane Switching
Organic Light Emitting Diode
|
|
Screen Shape
|
3:2 = 1.50
Aspect
Ratio
|
16:9 =
1.78
Aspect
Ratio
|
16:9 =
1.78
Aspect
Ratio
|
The iPhone 5 and Galaxy S III screens
have the same
shape as widescreen HDTV video content.
|
|
Screen Area
|
5.7 Square
Inches
|
6.7 Square
Inches
|
9.8 Square
Inches
|
A better measure of size than the
diagonal length.
|
|
Relative Screen Area
|
85 percent
|
100
percent
|
146
percent
|
Screen Area relative to the iPhone 5.
|
|
Display Resolution
|
960 x 640
pixels
|
1136 x 640
pixels
|
1280 x 720
pixels
|
The more Pixels and Sub-Pixels the
better.
|
|
Pixels Per Inch
|
326 PPI
Excellent
|
326 PPI
Excellent
|
PenTile
306 PPI
Very Good
|
At 12 inches from the screen 20/20 vision
is 286 ppi.
See this on
the visual acuity for a true Retina Display
|
|
Sub-Pixels Per Inch
|
Red 326
SPPI
Green 326
SPPI
Blue 326
SPPI
|
Red 326
SPPI
Green 326
SPPI
Blue 326
SPPI
|
Red 216
SPPI
Green 306
SPPI
Blue 216
SPPI
|
PenTile displays have only half the number
of Red
and Blue Sub-Pixels as standard RGB
displays.
For our analysis of PenTile see the OLED
Shoot-Out.
|
|
Total Number of Sub-Pixels
|
Red 614
KSP
Green 614
KSP
Blue 614
KSP
|
Red 727
KSP
Green 727
KSP
Blue 727
KSP
|
Red 462
KSP
Green 922
KSP
Blue 462
KSP
|
Number of Kilo Sub-Pixels KSP for Red,
Green, Blue.
PenTile displays have only half the number
of Red
and Blue Sub-Pixels as standard RGB
displays.
|
|
20/20 Vision Retina Display
down to this Viewing Distance
|
20/20
“Retina Display”
to 10.5
inches Viewing
|
20/20
“Retina Display”
to 10.5
inches Viewing
|
20/20
“Retina Display”
to 11.2
inches Viewing
Red / Blue
to 15.9 inches
|
For 20/20 Vision the minimum Viewing
Distance
where the screen appears perfectly sharp
to the eye.
|
|
Gallery / Photo Viewer Color Depth
|
Full
24-bit color
No
Dithering Visible
256
Intensity Levels
|
Full
24-bit color
No
Dithering Visible
256
Intensity Levels
|
Full
24-bit color
No
Dithering Visible
256
Intensity Levels
|
Most Android Smartphones and Tablets still
have some
form of 16-bit color depth
in the Gallery Photo Viewer
|
|
|
iPhone 4
|
iPhone 5
|
Galaxy S III
|
|
|
Overall Assessments
This section summarizes
the results of all of the extensive Lab measurements and viewing tests
performed on all of the displays.
The iPhone 5 display significantly
outperforms the displays on the Galaxy S III and iPhone 4. See all the
measurements below.
|
|
Viewing Tests
|
Good
Images
Photos and
Videos
have too
little color
and too
much contrast
|
Very Good
Images
Photos and
Videos
have
accurate color
and
accurate contrast
|
Good
Images
Photos and
Videos
have too
much color
and
accurate contrast
|
The Viewing Tests examined the accuracy
of
photographic images by comparing the
displays
to a calibrated studio monitor and HDTV.
|
|
Variation with Viewing Angle
|
Small
Color Shifts
with
Viewing Angle
Large
Brightness Shift
with
Viewing Angle
|
Small
Color Shifts
with
Viewing Angle
Large
Brightness Shift
with
Viewing Angle
|
Medium
Color Shifts
with
Viewing Angle
Medium
Brightness Shift
with
Viewing Angle
|
Color Shifts are more objectionable than
Brightness Shifts with Viewing Angle.
IPS LCDs have Small Color Shifts.
All LCDs have Large Brightness Shifts
|
|
Overall Display Assessment
Lab Tests and Measurements
|
Very Good LCD Display
|
Excellent LCD Display
|
Very Good OLED Display
|
These Flagship displays are all Very
Good to Excellent.
|
|
Overall Display Calibration
Lab Tests and Viewing Tests
|
Very Good Calibration
|
Excellent Calibration
|
Calibration Needs
Major Improvement
|
The Galaxy S III has a non-existent Poor
Color Gamut
display calibration that needs Major
Improvement.
|
|
Overall Display Grade
|
A–
|
A
|
B+
|
The iPhone 5 display performs
significantly better
than the iPhone 4 and the Galaxy S III
displays.
|
|
|
iPhone 4
|
iPhone 5
|
Galaxy S III
|
|
|
All of these screens are large mirrors good enough
to use for personal grooming – but it’s actually a very bad feature…
We measured the light reflected from all directions
and also direct mirror (specular) reflections, which are much more
distracting and cause more eye strain. The 10 – 15
percent reflections can make the screen much harder to read even
in moderate ambient light levels, requiring ever
higher brightness settings that waste precious battery power. Hopefully
manufacturers will reduce the mirror reflections
with anti-reflection coatings and haze surface finishes.
The iPhone 5 has significantly lower Reflectance
than the iPhone 4 – the iPhone 4 reflects 52 percent more Ambient Light.
|
|
Average Screen Reflection
Light From All Directions
|
Reflects 7.0 percent
Very Good
|
Reflects 4.6
percent
Excellent
|
Reflects
5.0 percent
Excellent
|
Measured using an Integrating
Hemisphere.
The best value we have measured is 4.4
percent
and the current worst is 14.8 percent.
|
|
Mirror Reflections
Percentage of Light Reflected
|
8.1 percent
Good
|
6.1 percent
Very Good
|
7.1 percent
Very Good
|
These are the most annoying types of
reflections.
Measured using a narrow collimated
pencil beam of
light reflected off the screen.
|
|
|
iPhone 4
|
iPhone 5
|
Galaxy S III
|
|
|
Brightness and Contrast
The Contrast Ratio is the specification that gets
the most attention, but it only applies for low ambient light, which is
seldom
the case for mobile displays. Much more important
is the Contrast Rating, which indicates how easy it is to read the screen
under high ambient lighting and depends on both the
Maximum Brightness and the Screen Reflectance.
The Galaxy S III has a
very low Maximum Brightness when the entire screen is white or has a white
background.
The low Galaxy S III Brightness is the result of
Power Management to maintain a satisfactory Battery Running Time.
The low Galaxy S III Brightness is responsible for
its lower Contrast Rating for High Ambient Light.
The iPhone 5 has the highest Contrast Rating for
High Ambient Light that we have ever measured.
|
|
Measured Maximum Brightness
100% Full Screen White
|
Brightness
541 cd/m2
Excellent
|
Brightness
556 cd/m2
Excellent
|
Brightness
224 cd/m2
Poor
|
Maximum Brightness is very important for
mobile
because of the typically high ambient
light levels.
|
|
Measured Peak Brightness
1% Full Screen White
|
Brightness
541 cd/m2
Excellent
|
Brightness
556 cd/m2
Excellent
|
Brightness
283 cd/m2
Good
|
This is the Brightness for a screen that
has only a tiny 1% Average Picture
Level.
|
|
Black Level
at Maximum Brightness
|
Black is
0.48 cd/m2
Very Good
for Mobile
|
Black is
0.41 cd/m2
Very Good
for Mobile
|
Less than
0.005 cd/m2
Outstanding
|
Black brightness is important for low
ambient light,
which is seldom the case for mobile
devices.
|
|
Contrast Ratio
Relevant for Low Ambient Light
|
1,117
Very Good
for Mobile
|
1,356
Very Good
for Mobile
|
Greater
than 45,000
Outstanding
|
Only relevant for low ambient light,
which is seldom the case for mobile
devices.
Defined as Maximum Brightness / Black
Brightness.
|
|
Contrast Rating
for High Ambient Light
|
Bright
Contrast 77
Very Good
|
Bright
Contrast 121
Excellent
|
Bright Contrast 45 - 57
Good
|
Defined as Maximum Brightness / Average Reflectance.
|
|
Screen Readability in Bright Light
|
Very Good A–
|
Excellent A
|
Good B
|
Indicates how easy it is to read the
screen
under high ambient lighting. Very
Important!
See High
Ambient Light Screen Shots
|
|
|
iPhone 4
|
iPhone 5
|
Galaxy S III
|
|
|
The Color Gamut, Intensity Scale, and White Point
determine the quality and accuracy of all displayed images and all
the image colors. Bigger is definitely Not Better
because the display needs to match all the standards that were used
when the content was produced. For LCDs a wider
Color Gamut reduces the power efficiency and the Intensity Scale
affects both image brightness and color mixture
accuracy.
The iPhone 5 has a Very Good display
calibration, but it is not quite as accurate as the Excellent calibration on
new iPad
because its Intensity Scale Gamma is a
bit too high, which upsets both the image contrast and color accuracy
somewhat.
It is still probably more accurate than
any display you own, unless you have a new iPad. See the Color Gamut and
Intensity Scale figures
for details and explanations.
|
|
White Color Temperature
|
7,781
degrees Kelvin
Somewhat
Too Blue
|
7,461
degrees Kelvin
Somewhat
Too Blue
|
7,860
degrees Kelvin
Somewhat
Too Blue
|
D6500 is the standard color of White for
most content
and necessary for accurate color
reproduction.
|
|
Color Gamut
See Figure 2
|
Gamut Too
Small
64 percent
of Std
See Figure 2
|
Essentially
Perfect
104
percent of Std
See Figure 2
|
Gamut Too
Large
139
percent of Std
See Figure 2
|
sRGB / Rec.709 is the color standard for
most
content and needed for accurate color
reproduction.
Note that Too Large a Color Gamut is
visually
worse than Too Small.
|
|
Dynamic Brightness
|
None
Excellent
|
None
Excellent
|
21 percent
|
This is the percent Brightness reduction
with APL
Average Picture Level. Ideally should be
0 percent.
|
|
Intensity Scale and Image Contrast
See Figure 3
|
Very
Smooth But
Contrast
Too High
See Figure 3
|
Very
Smooth
Contrast
is Very Good
See Figure 3
|
Very
Smooth
Contrast
is Very Good
See Figure 3
|
The Intensity Scale controls image
contrast needed
for accurate image reproduction. See Figure 3
|
|
Gamma for the Intensity Scale
Larger means more Image Contrast
See Figure 3
|
Good 2.68
Straight
and Constant
Gamma Too
High
|
Very
Good 2.36
Straight
and Constant
Slightly
Too High
|
Very Good
2.38 But
Dim-end
Steepens 2.73
Slightly
Too High
|
Gamma is the slope of the Intensity
Scale.
Gamma of 2.20 is the standard and needed
for
accurate image reproduction. See Figure 3
|
|
|
iPhone 4
|
iPhone 5
|
Galaxy S III
|
|
|
Viewing Angles
The variation of
Brightness, Contrast, and Color with viewing angle is especially important
for Smartphones because of
their large screen and
multiple viewers. The typical manufacturer 176+ degree specification for LCD
Viewing Angle
is nonsense because that
is where the Contrast Ratio falls to a miniscule 10. For most LCDs there are
substantial
degradations at less
than ±30 degrees, which is not an atypical viewing angle for Smartphones. IPS
LCDs generally do well.
Note that the Viewing
Angle performance is also very important for a single viewer because the
Viewing Angle varies based
on how the Smartphone is
held, and the angle can be very large if the Smartphone is resting on a table
or desk.
IPS LCDs have smaller
Color Shifts than OLEDs because OLEDs need more anti-reflection correction,
which has greater absorption
at larger angles. The
Galaxy S III has a surprisingly large Brightness Decrease for an OLED due to
its anti-reflection absorption.
|
|
Brightness Decrease
at a 30 degree Viewing Angle
|
57
percent Decrease
Very Large
Decrease
|
60 percent
Decrease
Very Large
Decrease
|
28
percent Decrease
Large
Decrease
|
Most screens become less bright when
tilted.
OLED decrease is due to anti-reflection
absorption..
LCD brightness variation is generally
very large.
|
|
Contrast Ratio
at a 30 degree Viewing Angle
|
556
Very Good
for Mobile
|
594
Very Good
for Mobile
|
Extremely
High
Not
Measured
|
A measure of screen readability when the
screen
is tilted under low ambient lighting.
|
|
Primary Color Shifts
at a 30 degree Viewing Angle
|
Small
Color Shift
Δ(u’v’)
= 0.0096
2.4 times
JNCD
|
Small
Color Shift
Δ(u’v’)
= 0.0077
1.9 times
JNCD
|
Small
Color Shift
Δ(u’v’)
= 0.0234
5.9 times
JNCD
|
JNCD is a Just Noticeable Color Difference.
IPS LCDs have smaller color shifts with
angle.
|
|
Color Shifts for Color Mixtures
at a 30 degree Viewing Angle
Reference Brown (255, 128, 0)
|
Small
Color Shift
Δ(u’v’)
= 0.0097
2.4 times
JNCD
|
Small
Color Shift
Δ(u’v’)
= 0.0098
2.4 times
JNCD
|
Medium
Color Shift
Δ(u’v’)
= 0.0168
4.2 times
JNCD
|
JNCD is a Just Noticeable Color Difference.
Color Shifts for non-IPS LCDs are about 10
JNCD.
Reference Brown is a good indicator of
color shifts
with angle because of unequal drive
levels and
roughly equal luminance contributions
from
Red and Green.
|
|
|
iPhone 4
|
iPhone 5
|
Galaxy S III
|
|
|
The display power was measured using a Linear
Regression between Luminance and AC Power with a fully charged battery.
Since the displays have different screen sizes and
maximum brightness, the values were also scaled to the
same screen brightness (Luminance) and screen area
in order to compare their relative Power Efficiencies.
The LCD display on he iPhone 5 is less power
efficient than the iPhone 4 because of its larger Color Gamut.
The OLED display on the Galaxy S III is
significantly less power efficient than the iPhone LCD displays.
OLEDs are improving but they are currently still
less power efficient than the best LCDs.
|
|
Display Power
at Maximum Brightness
|
0.42 watts
|
0.74 watts
|
1.3 watts
|
Lower power consumption is important for
energy
efficiency and improving running time on
battery.
|
|
Display Relative Power Efficiency
same Peak Luminance 556 cd/m2
same 4.0 inch screen size area
|
0.51 watts
|
0.74 watts
|
2.2 watts
|
This compares the Relative Power
Efficiency
by looking at the same screen brightness
and
screen area.
|
|
|
iPhone 4
|
iPhone 5
|
Galaxy S III
|
|
|
Running Time on Battery
The running time on battery was determined with the
Brightness sliders at Maximum, in Airplane Mode,
with no running applications, and with Auto
Brightness turned off.
Note that Auto Brightness can have a considerable
impact on running time but we found abysmal performance for
both the iPhone and Android Smartphones in our BrightnessGate analysis of Ambient Light Sensors
and Automatic
Brightness. They all need a more convenient Manual
Brightness Control as described in the BrightnessGate article.
At Maximum Brightness the iPhone 5 has
a shorter Running Time than the iPhone 4, which is not surprising since it
has a larger screen and a larger Color
Gamut but roughly the same capacity battery. The lower Brightness limitations
on the Galaxy S III are needed to
maintain a satisfactory Running Time.
|
|
Running Time
at the Maximum Display Power
|
7.8 hours
Excellent
|
6.6 hours
Very Good
|
5.6 hours
Very Good
|
Display always On at the Maximum setting
with
Airplane Mode and no running
applications.
|
|
Categories
|
iPhone 4
|
iPhone 5
|
Galaxy S III
|
Comments
|
About the Author
Dr. Raymond Soneira is
President of DisplayMate Technologies Corporation of Amherst, New Hampshire,
which produces video calibration, evaluation, and diagnostic products for
consumers, technicians, and manufacturers. See www.displaymate.com. He is a research
scientist with a career that spans physics, computer science, and television
system design. Dr. Soneira obtained his Ph.D. in Theoretical Physics from
Princeton University, spent 5 years as a Long-Term Member of the world famous
Institute for Advanced Study in Princeton, another 5 years as a Principal
Investigator in the Computer Systems Research Laboratory at AT&T Bell
Laboratories, and has also designed, tested, and installed color television
broadcast equipment for the CBS Television Network Engineering and Development
Department. He has authored over 35 research articles in scientific journals in
physics and computer science, including Scientific American. If you have any
comments or questions about the article, you can contact him at dtso.info@displaymate.com.
DisplayMate Display Optimization Technology
All
Smartphone and Tablet displays can be significantly improved using
DisplayMate’s advanced scientific analysis and mathematical display modeling
and optimization of the display hardware, factory calibration, and driver
parameters. We help manufacturers with expert display procurement and quality
control so they don’t make mistakes similar to those that are exposed in our
Display Technology Shoot-Out series. We can also improve the performance of any
specified set of display parameters. This article is a lite version of our
intensive scientific analysis – before the benefits of our DisplayMate Display Optimization
Technology, which can correct or improve all of these issues. If you are a
display or product manufacturer and want to significantly improve display
performance for a competitive advantage then Contact DisplayMate Technologies.
About DisplayMate Technologies
DisplayMate Technologies specializes in proprietary
sophisticated scientific display calibration and mathematical display
optimization to deliver unsurpassed objective performance, picture quality and
accuracy for all types of displays including video and computer monitors,
projectors, HDTVs, mobile displays such as smartphones and tablets, and all
display technologies including LCD, OLED, 3D, LED, LCoS, Plasma, DLP and CRT. This article is a lite version of
our intensive scientific analysis of Smartphone and Smartphone mobile displays
– before the benefits of our advanced mathematical DisplayMate Display Optimization
Technology, which can correct or improve many of the display deficiencies. We offer DisplayMate display
calibration software for consumers and advanced DisplayMate display diagnostic
and calibration software for technicians and test labs.
For manufacturers
we offer Consulting Services that include advanced Lab testing and evaluations,
confidential Shoot-Outs with competing products, calibration and optimization
for displays, cameras and their User Interface, plus on-site and factory
visits. See our world renown Display
Technology Shoot-Out public article series for an introduction and preview.
DisplayMate’s
advanced scientific optimizations can make lower cost panels look as good or
better than more expensive higher performance displays. For more information on
our technology see the Summary description of our Adaptive Variable Metric Display
Optimizer AVDO. If you are a display or product manufacturer
and want to turn your display into a spectacular one to surpass your
competition then Contact
DisplayMate Technologies to learn more.
Article Links: Apple new
iPad, iPad 2, and iPhone 4 Display Technology Shoot-Out
Article Links: Display Technology Shoot-Out
Article Series Overview and Home Page
Copyright © 1990-2012 by DisplayMate
Technologies Corporation. All Rights Reserved.
This article, or any part
thereof, may not be copied, reproduced, mirrored, distributed or incorporated
into any other work without
the prior written permission of DisplayMate Technologies Corporation
