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Tablet Screen Areas, PPI & Aspect Ratios

32K views 24 replies 9 participants last post by  Tablet_Collector 
#1 · (Edited by Moderator)
7" (aspect ratio 16:10) - Screen Area = 22.02 inches squared
(16x)^2 + (10x)^2 = 7^2
356(x^2) = 49
x = 0.371
16 * 0.371 = 5.936
10 * 0.371 = 3.71
Screen Area = 5.936 * 3.71 = 22.02 inches squared

8" (aspect ratio 4:3) - Screen Area = 30.72 inches squared
(4x)^2 + (3x)^2 = 8^2
16x^2 + 9x^2 = 64
25x^2 = 64
x^2 = 64/25
x^2 = 2.56
x = sqrt(2.56) = 1.6
4*1.6= 6.4 inches
3*1.6=4.8 inches
Screen Area = 6.4 * 4.8 = 30.72 inches squared

9.4" (aspect ratio 16:10) - Screen Area = 39.71 inches squared
(16x)^2 + (10x)^2 = 9.4^2
356(x^2) = 88.36
x = 0.4982
16*0.4982 = 7.971
10*0.4982 = 4.982
Screen Area = 7.971 * 4.982 = 39.71 inches squared

9.7" (aspect ratio 4:3) - Screen Area = 45.16 inches squared
(4x)^2 + (3x)^2 = 9.7^2
25(x^2) = 94.09
x=1.94
4*1.94=7.76
3*1.94=5.82
Screen Area = 7.76 * 5.82 = 45.16 inches squared

10.1" (aspect ratio 16:10) - Screen Area = 45.85 inches squared
(16x)^2 + (10x)^2 = 10.1^2
356(x^2) = 102.01
x = 0.5353
16*0.5353 = 8.5648
10*0.5353 = 5.353
Screen Area = 8.5648 * 5.353 = 45.85 inches squared

Notes on aspect ratios:
#1. 16:10 is the standard Android aspect ratio. 4:3 works too but a] gives black bars on top and bottom of HD video rips and b] some games maybe stretched out
#2. 4:3 is better for reading, typing and working on. 16:10 has best compatibility with Android games & HD video.
#3. Lots of reading, typing and web browsing. Get 4:3 (8" & 9.7") tablet. Lots of gaming & video watching. Get 16:10 (7", 9.4" or 10.1") tablet.

Edit: added in 9.4" size from Jez's post.
 
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#3 · (Edited by Moderator)
Superb stuff nikos, thanks!
Thanks yash. Good to see the difference in screen areas. I am also including percentages when going from one screen size to the next.

Screen Area Difference Between Tablets As Percentage:
7" versus 8" = (30.72 - 22.02)/22.02 = 39.51%
7" versus 10.1" = (45.85 - 22.02)/22.02 = 108.22%
8" versus 10.1" = (45.85 - 30.72)/30.72 = 49.25%

I left out 9.7" because too close area to 10.1" and will give similar results.

Just by choosing 8" you get almost 40% more screen area over 7". But 4:3 aspect ratio means black bars on HD video rips and some games may become stretched or not work.

7" to 10.1" is huge difference in screen area. 8" to 10.1" is kinda big but not massive difference.

PPI (Pixels Per Inch) For Android Tablets:

7" 800x480 - 133 PPI
7" 1024x600 - 170 PPI
7" 1280x800 - 216 PPI

8" 800x600 - 125 PPI
8" 1024x768 - 160 PPI
8" 2048x1536 - 320 PPI (coming 2013)

9.4" 1280x800 - 161 PPI

9.7" 1024x768 - 132 PPI
9.7" 2048x1536 - 264 PPI (coming 2013)

10.1" 1024x600 - 118 PPI
10.1" 1280x800 - 149 PPI
10.1" 1920x1200 - 224 PPI (2 or 3 tablets have it)
10.1" 2560x1600 - 299 PPI (Nexus 10)

Edit: added in 9.4" PPI from Jez's post. 160.57 rounded up to 161. =) Also, changed ppi to PPI.
 
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#5 ·
Added in PPI (pixels per inch) for Android tablets in post #3.
 
#6 · (Edited by Moderator)
This is an awesome guide for those of us looking to get a tablet, might I suggest adding the aspect ratio to each one for a quick reference. Also might I suggest a mod sticky this badboy?


One thing to add for those looking is downloading the gimp image editor, it allows you to create a canvas using inches giving you an easy way to size it up, though I have to turn off dot for dot under view to get mine to size correctly on screen.

Heres an image I made of the different sizes, 8 inch, 9.7inch, 7 inch, then 10.1 inch in order from left to right; though only sizes correctly on 20 inch monitor like my own unfortunately. ><
http://i.imgur.com/JzdvI.jpg
 
#7 · (Edited by Moderator)
This is an awesome guide for those of us looking to get a tablet, might I suggest adding the aspect ratio to each one for a quick reference. Also might I suggest a mod sticky this badboy?
OK. Added in aspect ratios and notes to 1st post to make it more informative. Later,

Edit: changed thread name to better reflect the info found in here
 
#10 ·
Why do you really need 'retina display' (higher res)?
Bragging right? Clarity? Apple hype?
Yes well, I only realized about the battery drain difference just recently. =) Around 2 days back. Never looked into it before that and never crossed my mind there would be more battery drain with higher resolution until Ivanz pointed it out. ie, never thought about how resolution affected battery life or checked/compared iPad 2 & 3 battery life. I learn new things here & there too! =)

I agree that 1280x800 is great for 7" (very high PPI) and very good still for 10.1". 1024x768 is great for 8". Problem is with 9.7" which has somewhat low PPI at 1024x768. I have seen it said that 150 PPI or higher is ideal for very good clearness & sharpness. I believe that is the minimum PPI to have. My i7 has 133 PPI and looks pixelated. Can really see it when zoomed in.

Tablet PPIs
http://www.slatedroid.com/topic/41222-tablet-screen-areas-ppi-aspect-ratios/page__view__findpost__p__457022

Here is a very good article on Retina VS non-Retina display:
http://tabletrepublic.com/forum/latest-tablet-news/buy-not-buy-retina-tablet-3021.html

Many Chinese tablet makers will be coming out with high resolution displays but hopefully they keep around the normal/standard resolutions too. I would probably only consider a slightly-somewhat higher resolution than 1024x768 for 9.7" tablet because PPI is too low for that one.

PS, Just to show the effect on battery life with higher resolution. iPad 2&3 info taken from Wikipedia:
iPad2, 10 hours on 6800 mAh battery. ie. consumes 680 mAh per hour
iPad3, 8 hours on 11,500 mAh battery. ie. consumes 1437 mAh per hour

#1. iPad3 uses twice the amount of energy of iPad2.
#2. IF iPad3 came with 6800 mAh battery it would run for 4.73 hours (or 4 hours 44 mins) (6800/1437) off battery power. ie. half the # of hours the iPad2 would run for. ie. over 100% (or 2X) difference in battery life.

PPS, part of this is probably because of newer A5X chip compared to A5. More energy consumption.

The newer A31 & RK3188 use about half the power (on the CPU side) of the RK3066. So, should be very interesting to see how that impacts battery life at standard and high resolutions.
 
#13 · (Edited by Moderator)
I just have a question, is the compatibility for games on 4:3 hindered much, or is it only a few games that don't work? I'm looking for a tablet, and I have two in mind, one is 4:3 and the other is 16:10, that is why I ask
UPDATE:
All games I have tested so far appear to work.

How games are handled on 4:3 tablet (8" & 9.7").
#1. Game data is made to fit 4:3 display. In which case it will work perfectly. ie. Men in Black, Asphalt 7
#2. Game data is for 16:10 tablet which Android OS will provide a button bottom right to deal with this issue.
The button allows choice between:
a] stretch b] zoom (looks pixelated) and c] fill. Fill is 5" or 6" 16:10 version of the game. Fill has black bars on top, bottom & sides.

Stretch is the best and will work for many, if not all, 16:10 games. Like Farm Frenzy 3. A perfectly stretched game will only have black bars on top & bottom. Fill is more of a last resort if stretch does not work. Zoom looks pixelated so I avoid using that mode.

Edit: changed content. Updated based on what I learned using my 8" tablet.
 
#14 ·
I updated my previous post.

So why not 1280/960
= 4:3 ?
8" tablets used to have 800x600 with single core CPUs and then moved up to 1024x768. Lots of 7" were 800x480 with the early single core CPUs. Later adding 1024x600. Now some 7" have 1280x800 too.

ie. resolutions are starting to increase. 1024x768 is good for 8" but on the low side for 9.7".

I agree that 1280x960 would be very good and the ideal resolution for 4:3 tablets. It would be high enough to have very sharp text & graphics, playback 720p video, still provide great 3D game performance and good battery life too. That is the resolution I would want on 9.7". On 8", I could still live with 1024x768 because still good for it (160 PPI).

See here for resolutions for different aspect ratios:
http://en.wikipedia.org/wiki/File:Vector_Video_Standards4.svg

PS, higher resolutions require stronger GPUs to properly handle 3D gaming. The dual core chips have much better & powerful GPUs but still not great for very high resolutions.
 
#15 · (Edited by Moderator)
Useful stuff, thanks Nickos-V


Could always add the 9.4 inch tablet details e.g. Pipo M8, Ramos W42, Sony Tablet S etc.

I make it...
9.4" (aspect ratio 16:10) - Screen Area = 39.71 inches squared
(16x)^2 + (10x)^2 = 9.4^2
356(x^2) = 88.36
x = 0.4982
16*0.4982 = 7.971
10*0.4982 = 4.982
Screen Area = 7.971 * 4.982 = 39.71 inches squared

PPI:

9.4" 1280x800 - 160 PPI

Cheers
Jez
 
#16 ·
Could always add the 9.4 inch tablet details e.g. Pipo M8, Ramos W42, Sony Tablet S etc.
Thanks Jez. I added 9.4" details to my two posts above.

Very interesting that 9.4" 1280x800 has same PPI as 8" 1024x768. 160 PPI is fairly sharp though I can see slight blurriness with very small fonts. That is why I now prefer having 160 PPI or higher for tablets. I can only imagine how bad small fonts will look on 10.1" with 149 PPI or 9.7" with 132 PPI.

10.1" @ 1280x800 & 9.7" @ 1024x768 have too low PPI. 7" tablets have very good PPI but too little screen space for me. I really am liking 8" over 7". 8" & 9.4" at standard resolutions look like the best tablet choices. Great 3D performance, very good PPI and great battery life. Retina (high resolution) displays sound great but they really impact 3D performance & battery life which makes them not worth it for me.

Later,
 
#21 ·
Hi JJovian,

Thanks for the link but my Trend Internet Security says this is a dangerous page.
Do you know whether this is a false positive? i.e. can you vouch for the safety of the page?

Thanks
Jez
 
#20 ·
By the way, janesh posted a link to a Chinese review of the Ramos W42 and within this review is a very clear illustration of the difference in display clarity between the 9.4 inch 1280 x 800 and 9.7 inch 1024 x 768...HERE

Jez
 
#23 ·
Ok thanks, it doesn't surprise me as it's not the first time Trend has given me a false positive. I am seriously thinking of ditching it for Kapersky.

Sorry about that.
Jez
 
#25 · (Edited by Moderator)
Hmmm, decisions. Of course I can get Kapersky free with my banking


Maybe I will try it and then decide.

Thanks
Jez
Sorry for Off Topic
 
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