[Information] SGS4 sub-pixel density compared with other leading phones

[mcimo88]

Please take the information I am providing with a grain of salt, I own only one of these devices (the Galaxy Nexus). I am providing this information purely for the sake of knowledge and research. Certainly, the best way to know which is the best display for you is to see them in person and decide for yourself. If anyone would like me to add any more phones to the list, please let me know.

That said, the one statistic many reviewers have not provided is what I like to refer to as SPPI, or sub-pixels per inch. In my opinion (which is all I can provide) SPPI is a MUCH more important number than PPI (pixels per inch). Although I can not prove so, I believe that while the human eye combines sub-pixels for COLOR, we resolve SHARPNESS from SPPI and NOT from traditional PPI; hence technologies such as Microsoft's ClearType, which are able to provide text that is up to 3 times sharper (in one direction) than the display's PPI would otherwise allow.

I will also include what I will call "Relative RGB PPI" for the PenTile displays; this will be calculated based on how many pixels the display would have per inch if it had the same SPPI, but with a full RGB arrangement instead of PenTile. The formula I use for this is as follows: (PPI*2)/3=Relative RGB PPI. The RGB stripe displays will only have "True PPI" because every pixel is capable of displaying every possible color. This will give a somewhat more accurate depiction of pixel density than is provided by traditional methods. Well, on to the numbers!


Samsung Galaxy Nexus
Resolution: 1280x720
Screen size: 4.65 inches (16:9 AR)
Sub-pixel arrangement: RG BG PenTile stripe
Traditional PPI: 315
Relative RGB PPI: 210
Sub-pixels per inch: 630

LG Nexus 4
Resolution: 1280x768 (3:2 AR)
Screen size: 4.7 inches
Sub-pixel arrangement: RGB stripe
True PPI: 320
Sub-pixels per inch: 960

Samsung Galaxy S4
Resolution: 1920x1080
Screen size: 4.99 inches (16:9 AR)
Sub-pixel arrangement: RG BG PenTile diagonal/hexagonal
Traditional PPI: 441
Relative RGB PPI: 294
Sub-pixels per inch: 882

HTC One
Resolution: 1920x1080 (16:9 AR)
Screen size: 4.7 inches
Sub-pixel arrangement: RGB stripe
True PPI: 468
Sub-pixels per inch: 1404

 

[hung2900]

Firstly, you should calculate again. You have the wrong calculation for the sub-pixels per inch and what you called "True PPI" of Pentile screen.

Secondly, you don't understand anything about Pentile technology. It takes the advantage of strong luminance green pixels of OLED to reduce the number of total sub-pixels without making a big depression on sharpness. If you say the sharpness depends on the number of sub-pixels only, so this technology is useless? Besides, it also depends on the stripe layout. On S4, it's diamond shape, which is way better than the implementation on S3

The redundant space is minimal and to be the same, not different big-small gaps flike on S3 (which is one of the main culprit of Jagginess on S3)
_______________________
Edit: To be clear here, here are the calculation for subpixels per inch.
1920 x 1080 at 4.7"(HTC One), 3 subpixels per pixel -> 6,220,800 subpixels = 3,325.5 x 1,870.6 subpixels (16:9)
811 subpixels per inch
1920 x 1080 at 5" (Samsung Galaxy S4), 2 subpixels per pixel -> 4,147,200 subpixels = 2,715.3 x 1,527.3 subpixels (16:9)
623 subpixels per inch

In addition, the subpixels per inch of iPhone 5 (329ppi) is 565 and of Z10 (347 ppi) is 615.
And here is the comparison of sharpness, S4 (what you said has the "True PPI" of 294) looks way sharper than iPhone 5 (with the so-called Retina display) under the microscope

 

[mcimo88]

You should calculate again

Did I miscalculate somewhere?

 

[Azurael]

You should calculate again

Well that was an informed and helpful response...

The numbers seem to correlate with my experience with pentile displays. I still find the subpixels a bit jarring on 720 amoleds, but I have to be looking for them, unlike my old HTC Desire or Moto Atrix. However, it's also worth pointing out that you only need around 300dpi to lose the individual pixels at typical phone viewing distances so it seems plausible you might not be able to see a difference in sharpness between an S4 and an HTC One. I've not seen any of the FHD devices but I'm guessing any improvements in the LCD are more from technological progression than higher resolution where the amoled actually gains from the higher resolution.

Personally, I'd prefer a smaller device with a 4.5" 720p rgb amoled display (as calibrated by HTC, not Samsung!) to any of the current options but manufacturers like to tick boxes like 'biggest' and 'highest resolution'.

Sent from my Nexus 4 using xda app-developers app

 

[hung2900]

Did I miscalculate somewhere?

I edited above.

 

[mcimo88]

Well that was an informed and helpful response...

The numbers seem to correlate with my experience with pentile displays. I still find the subpixels a bit jarring on 720 amoleds, but I have to be looking for them, unlike my old HTC Desire or Moto Atrix. However, it's also worth pointing out that you only need around 300dpi to lose the individual pixels at typical phone viewing distances so it seems plausible you might not be able to see a difference in sharpness between an S4 and an HTC One. I've not seen any of the FHD devices but I'm guessing any improvements in the LCD are more from technological progression than higher resolution where the amoled actually gains from the higher resolution.

Personally, I'd prefer a smaller device with a 4.5" 720p rgb amoled display (as calibrated by HTC, not Samsung!) to any of the current options but manufacturers like to tick boxes like 'biggest' and 'highest resolution'.

Sent from my Nexus 4 using xda app-developers app

I feel the same way about the sub-pixels being slightly jarring on Pen-tile displays with low to medium SPPI counts. My wife has a Droid RAZR for example, and the display on it destroys my eyes with a SPPI of 512. Certain colors look fine with PenTile, while others (red especially) look grainy. One thing I would imagine will help the display of the S4 besides having a high SPPI is the new arrangement of sub-pixels in a diagonal/hexagonal setup. Personally, the one thing that is really keeping me away from the S4 is the image retention/burn in and general uneven nature of AMOLED screens in general. In this case I will likely be going for the HTC One, which should be a more accurate display. I am hoping that Erica Griffin on YouTube can get one of her AMAZING reviews up for the S4, which could possibly sway my decision.

 

[hung2900]

I feel the same way about the sub-pixels being slightly jarring on Pen-tile displays with low to medium SPPI counts. My wife has a Droid RAZR for example, and the display on it destroys my eyes with a SPPI of 512. Certain colors look fine with PenTile, while others (red especially) look grainy. One thing I would imagine will help the display of the S4 besides having a high SPPI is the new arrangement of sub-pixels in a diagonal/hexagonal setup. Personally, the one thing that is really keeping me away from the S4 is the image retention/burn in and general uneven nature of AMOLED screens in general. In this case I will likely be going for the HTC One, which should be a more accurate display. I am hoping that Erica Griffin on YouTube can get one of her AMAZING reviews up for the S4, which could possibly sway my decision.

I don't think comparing the old Amoled to the new one is a good way. Samsung has improved their display significantly recently after each version.
About the color, you can switch to AdobeRGB mode or movie mode which is proved to have more accurate colors than iPhone 5 and HTC One.
And please read the my post above to see SPPI calculation

P/s: I love Erica Griffin reviews too

 

[GTRagnarok]

The S4 is a lot sharper than the iPhone (which I think is fine) so I have no worries.

 

[mcimo88]

Firstly, you should calculate again. You have the wrong calculation for the sub-pixels per inch and what you called "True PPI" of Pentile screen.

Secondly, you don't understand anything about Pentile technology. It takes the advantage of strong luminance green pixels of OLED to reduce the number of total sub-pixels without making a big depression on sharpness. If you say the sharpness depends on the number of sub-pixels only, so this technology is useless? Besides, it also depends on the stripe layout. On S4, it's diamond shape, which is way better than the implementation on S3

The redundant space is minimal and to be the same, not different big-small gaps flike on S3 (which is one of the main culprit of Jagginess on S3)
_______________________
Edit: To be clear here, here are the calculation for subpixels per inch.
1920 x 1080 at 4.7"(HTC One), 3 subpixels per pixel -> 6,220,800 subpixels = 3,325.5 x 1,870.6 subpixels (16:9)
811 subpixels per inch
1920 x 1080 at 5" (Samsung Galaxy S4), 2 subpixels per pixel -> 4,147,200 subpixels = 2,715.3 x 1,527.3 subpixels (16:9)
623 subpixels per inch

In addition, the subpixels per inch of iPhone 5 (329ppi) is 565 and of Z10 (347 ppi) is 615.
And here is the comparison of sharpness, S4 (what you said has the "True PPI" of 294) looks way sharper than iPhone 5 (with the so-called Retina display) under the microscope

I edited above.

I don't think comparing the old Amoled to the new one is a good way. Samsung has improved their display significantly recently after each version.
About the color, you can switch to AdobeRGB mode or movie mode which is proved to have more accurate colors than iPhone 5 and HTC One.
And please read the my post above to see SPPI calculation

P/s: I love Erica Griffin reviews too

Thank you for clarifying! For the record, I understand what PenTile technology is, and its purpose (to essentially increase the working resolution of the display beyond what current manufacturing methods will allow for full RGB sub-pixel arrangements). I also completely agree with you that the physical arrangement of the sub-pixels in PenTile displays is a very important factor in perceived sharpness. Further, I believe Samsung got it right with their hexagonal pattern of sub-pixels on the GS4 (way to go Sammy!).

I'm not sure I am following your calculations; could you elaborate on how you arrived at these numbers? It looks like you may be calculating based on area. I could be wrong here, but logic tells me that if a screen had 100 pixels per inch, and each pixel contains 3 sub-pixels, it should have 300 sub-pixels per inch; in other words, SPPI = PPI times the number of sub-pixels per pixel.

Again, I am not claiming to be any kind of mathematician, so please correct me if I am wrong!

And yes, Erica Griffin's reviews are awesome!