42 / 38 ppi ?

Discussion in 'Apple Watch' started by Mapple86, May 24, 2015.

  1. Mapple86 macrumors regular

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    Apr 13, 2015
    #1
    Hi,

    Well i found manny different statements aboutth ppi of both models.
    First i found that the 38 is 290ppi and 42 is 302ppi.
    Now sone people are telling they have both exactly 326ppi.
    Anybody here can tell me what is the truth about the ppi?
     
  2. albertsw, May 24, 2015
    Last edited: May 24, 2015

    albertsw macrumors regular

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    Apr 3, 2012
    #2
    290 and 302 is correct.

    Edit: they're both around 326.
     
  3. juniorspank, May 24, 2015
    Last edited: May 24, 2015

    juniorspank macrumors member

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    #3
    No, they're definitely both 326. http://en.wikipedia.org/wiki/Apple_Watch

    https://m.reddit.com/r/apple/comments/360j0r/note_the_apple_watch_has_a_pixel_density_of_326/
     
  4. melman101 macrumors 68030

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    #4
    I have no idea LOL
     
  5. juniorspank macrumors member

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    #5
    Except that they're both 326ppi

    https://m.reddit.com/r/apple/comments/360j0r/note_the_apple_watch_has_a_pixel_density_of_326/
     
  6. albertsw, May 24, 2015
    Last edited: May 24, 2015

    albertsw macrumors regular

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    #6

    That Wikipedia article literally says "unreliable source" under the 326 ppi specification.

    Edit: did some looking around and some math and it does seem like ~326 is correct.
     
  7. Crazy Matt macrumors 6502

    Crazy Matt

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  8. p3ntyne, May 24, 2015
    Last edited: May 24, 2015

    p3ntyne macrumors 6502

    p3ntyne

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    #8
    They are both (slightly above) 326 PPI when the exact screen size is taken into consideration (for the 42, I calculated 333 and for the 38, 332).

    290 and 302 PPI is calculated when the sizes of the watch are used for vertical height (38 or 42 mm). Since the screen is not the entire size of the watchface, both Apple watches have a PPI of >326.
     
  9. Crazy Matt macrumors 6502

    Crazy Matt

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    #9
    Sorce?
     
  10. p3ntyne, May 24, 2015
    Last edited: May 24, 2015

    p3ntyne macrumors 6502

    p3ntyne

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    #10
    My own calculations (which have been added in with an edit).

    The 42 mm watch has a resolution of 390x312 and a screen that is 38 mm diagonally. The 38 mm is 340x272 with a 33.3 mm screen. It's pretty easy to calculate.

    Also someone on reddit used a professional tool to measure theirs and got a figure close to 326 too.

    EDIT: now that I think about it, that's also slightly inaccurate since the PPI of both is 333 and 332.
     
  11. Lloydbm41 macrumors 68040

    Lloydbm41

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    #11
    Actually, no they both are not. But they are both pretty darn close and when it comes to any smartwatch on the market, I believe the Apple Watch trumps them all in the ppi department (at least until the new Android Wear watches get released from Motorola, Huawei, Samsung, etc.

    Anyway, based off the official Apple Watch SDK, we know the following:

    The 42mm Apple Watch has a 312px by 390px resolution and a diagonal screen measuring 39mm or 1.535in. This = 325.37ppi

    The 38mm Apple Watch has a 272px by 340px resolution and a diagonal screen measuring 36.048mm or 1.419in. This = 306.8ppi.

    See below for SDK info on dimensions/resolution figures.
     

    Attached Files:

  12. p3ntyne macrumors 6502

    p3ntyne

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    #12
    It seems that all sources show a different size for the display. In my calculations, I used 33.3 and 38 mm for the display sizes.
     
  13. Lloydbm41 macrumors 68040

    Lloydbm41

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    #13
    For the 38mm watch, the height and width is 38.6mmx33.3mm, so the diagonal is 36.048mm or 1.419inches.

    The 42mm watch has a height and width of 42mmx35.9mm, so the diagonal is 39mm or 1.535inches.

    I think I'll trust that Apple has it right in their own SDK.
     
  14. juniorspank macrumors member

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    Feb 9, 2015
    #14
    The height of the entire watch is not the height of the display, using 42mm and 38mm is incorrect and it's clearly proven on the reddit thread.

    Apple posted the schematics online and are shown here via Gruber's twitter: https://pbs.twimg.com/media/CFF8yNWWYAAUu37.png:large

    The image shows the active display area as 21.22mm x 26.52mm, which gives a diagonal of 33.96mm.

    33.96mm = 1.3370079 inches and plugging that number into a PPI calculator with the 272px by 340px, also officially from Apple, gives us 325.66ppi, effectively 326.

    So using all official information from Apple, the 38mm has a ~326ppi screen.
     
  15. Lloydbm41 macrumors 68040

    Lloydbm41

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    #15
    I stand corrected. I made a math error in my Pathagorean Theorum. Surprised I didn't get called out on that! Stupid me divided by 2 then square rooted the hypotenuse, instead of just square rooting the hypotenuse. Duh.

    I redid my calculations and you are perfect (if the active display area is what you posted).

    So, what is the active display area of the 42mm?
     
  16. juniorspank macrumors member

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    Feb 9, 2015
    #16
    Nobody likes math on the weekend!

    The 42mm has an active display area of 24.34mm x 30.42mm as shown here: https://pbs.twimg.com/media/CFF-k5dWEAEx7xw.png:large
     

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