c****o
发帖数: 681 | 1 Can anyone who actually got the device comment on this?
The Google Nexus 7 Display Stumbles and Falls Short
Dr. Raymond M. Soneira - DisplayMate
The Google Nexus 7 is the first of the second generation 7 inch Tablets out
of the gate. and it sure looks like it could be a winner. The published
display specs look pretty good, and some of the basic Lab measurements also
look pretty good. But just like in Triple Crown races, an important but
overlooked issue can spoil the outcome.
Dr. Raymond Soneira of DisplayMate Technologies has made it his mission to
suss out the best smartphone, tablet, HDTV, and multimedia displays from the
worst with his Display Technology Shoot-Out series. Here, he dissects the
screen on Google's Nexus 7.
In this Display News item we'll explain what went wrong with the Nexus 7
display - the details will appear in our upcoming in-depth 7 inch Tablet
Display Shoot-Out.
The display on the Nexus 7 sounds great on paper - a 1280x800 display with
216 Pixels Per Inch, within the PPI sweet spot we have recommended for
Tablets, so text and graphics appear very sharp, but not as sharp as on the
new iPad 3. It also has a premium IPS LCD, the same technology found on the
iPads and the first generation Kindle Fire, which provides excellent wide
viewing angles. In the Lab we measured the Nexus 7 Brightness (Luminance) to
be about 350 nits, comparable to most other 7 inch LCD Tablets. Its display
Contrast Ratio is about 1,000 which is excellent for mobile displays. So
far so good.
Next we measured the Color Gamut, something where almost all mobile LCDs
come up short in order to improve power efficiency and battery running time.
They typically provide only about 60 percent of the ideal Standard Color
Gamut, which results in somewhat subdued colors in all displayed images,
including photos and videos. For the Google Nexus 7 we measured an
impressive 86 percent of the Standard Gamut - not as good as the new iPad 3'
s 99 percent, but much better than most existing LCD Tablets and Smartphones
. So far, it sounds really good - but let's see how good it actually looks.
Even before I examined the display with our DisplayMate diagnostic test
patterns I knew something was seriously wrong when I looked at the first of
many sets of standard photos that we use to visually evaluate displays.
Normally we compare everything to a calibrated professional studio monitor
to check for image and color accuracy. But that wasn't necessary with the
Nexus 7 because many of the images were noticeably washed out - they looked
like over exposed photographs with missing highlights, reduced image
contrast, and weak colors. However, darker images look a lot better than
brighter ones, which actually tells us a lot about its cause.
So, what's the problem? The Intensity Scale (often called the Gray Scale) is
way off. The display's Brightness fails to increase sufficiently for bright
image content, causing bright image detail to be compressed and lost. See
the Figure at left for the Nexus 7 and this Figure to see what the Intensity
Scale should look like. The Nexus 7 Display Stumbles and Falls Short both
figuratively and literally.
There is about a 25 percent compression of bright image content, which is
quite substantial. This holds for both the Gallery Viewer and the Chrome
Browser. On some cheap displays this is done intentionally by the
manufacturer because the compression actually makes them appear artificially
bright. Here I think it's probably just incompetence by the manufacturer,
which is too bad because they messed up a really nice display. Depending on
the display firmware this may or may not be correctable with a software
update. These tests were made under Android 4.1.1.
The Nexus 7 has a high quality display, they just really messed up the
factory calibration. This affects all displayed images, but it is most
noticeable on any form of photographic image, including videos, because the
color and intensity mixtures are visually critical for them to look right.
The analogy of an over exposed photo is a good one. For high contrast
software generated text and graphics the display will look fine.
In short, the display produces washed out images and colors in spite of the
fact that it has a display with excellent color saturation and contrast.
Looks like Google didn't pay enough attention to the Steve Jobs memo that
the key to a successful Tablet is an outstanding display. If high image and
picture quality is important to you, then you might want to skip the Google
Nexus 7 and wait for a Tablet with a better display, or wait and see if
Google can correct the problem.
We'll provide all of the details in our upcoming 7 inch Tablet Display Shoot
-Out. We're now waiting for the rumored Apple mini iPad and the rumored new
Amazon Kindle Fire - the rumor drums are beating very loudly so we are
expecting a Shoot-Out very soon. Stay tuned. | s*i
发帖数: 5025 | 2 完全赞同！
我的第一感也是washed out。我以为是我习惯了AMOLED的缘故
out
also
the
[发表自未名空间手机版 - m.mitbbs.com]
【在 c****o 的大作中提到】
: Can anyone who actually got the device comment on this?
: The Google Nexus 7 Display Stumbles and Falls Short
: Dr. Raymond M. Soneira - DisplayMate
: The Google Nexus 7 is the first of the second generation 7 inch Tablets out
: of the gate. and it sure looks like it could be a winner. The published
: display specs look pretty good, and some of the basic Lab measurements also
: look pretty good. But just like in Triple Crown races, an important but
: overlooked issue can spoil the outcome.
: Dr. Raymond Soneira of DisplayMate Technologies has made it his mission to
: suss out the best smartphone, tablet, HDTV, and multimedia displays from the
| r*********n
发帖数: 4553 | | t***s
发帖数: 4666 | 4 did they turn off the auto brightness? try turn to the max.
【在 s*i 的大作中提到】
: 完全赞同！
: 我的第一感也是washed out。我以为是我习惯了AMOLED的缘故
:
: out
: also
: the
: [发表自未名空间手机版 - m.mitbbs.com]
| a***s
发帖数: 440 | 5 Washout is caused by wrong gamma, which means when u want show normalized 25
, for example, the display shows 30. Good calibration can be costly.
【在 t***s 的大作中提到】
: did they turn off the auto brightness? try turn to the max.
| c****o
发帖数: 681 | 6 Hmmm, AMOLED itself may not be a fair display to compare against.
【在 s*i 的大作中提到】
: 完全赞同！
: 我的第一感也是washed out。我以为是我习惯了AMOLED的缘故
:
: out
: also
: the
: [发表自未名空间手机版 - m.mitbbs.com]
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