Retina vs Non-Retina - iPhoto Zooms differently?

Discussion in 'iMac' started by icemantx, Nov 9, 2014.

  1. icemantx macrumors regular

    Mar 16, 2009
    So I was showing the new iMac Retina to my wife today along side of a non-Retina iMac today at our local Apple store. What we could not figure out is why when zooming in on a 24mp in iPhoto when using the non-Retina it zooms in so much further than on the Retina?

    Any ideas? There is likely a logical reason, but we could not figure it out.


  2. mad3inch1na macrumors 6502a

    Oct 21, 2013
    I don't know how much you know about the way retina works, so I will try to be thorough. The retina screen is just double the horizontal and vertical pixels of the regular screen (2560x1440 vs 5120x2880). At 27", a 2880p display can potentially display 4x the content of a 1440p display, but that content will be extremely small. To compensate for that, Apple made "HiDPI" mode, which means everything is blown up 4x to make content viewable.

    Text and most content is scaled up 4x, but pictures are not displayed in HiDPI mode. When you zoom in on both computers, they are actually zooming in the same amount, but there are 4x as many pixels on the retina iMac, so the picture looks smaller. This is important for content creators who want to edit in full 4k. I think pictures can be displayed in HiDPI mode, but by default they will scale 1:1 instead of the 4:1 used in HiDPI mode.

    TL;DR: Most content on the Retina iMac is scaled up 4x, but pictures are not. You perceive it as zooming less, but the pictures display the same amount of pixels on both computers. You can just see more content on the 5k display.


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