If Asus can get Google's new Nexus 7 to Retina-like densities while retaining its small, 7-inch form factor, why can't Apple do likewise and launch an iPad mini Retina already? That's a question that's been asked again and again since Google introduced the new Nexus 7 earlier this week. Here's the answer:
Last fall, when Apple launched the iPad mini, it was with their standard 1024x768 panel at 163ppi. Apple had to choose between lightness, Retina, and battery life. They could only have two of the three. For the full sized iPad, Apple chose Retina and battery life. For the iPad mini, lightness and battery life. (An iPad getting 5 hours on a full charge is a non-starter.) That's why Apple couldn't use Retina in the original iPad mini. So why can Asus? Well, they can't either. They're using 1080p, not Retina, and believe it or not, it makes a big difference.
To maintain app compatibility, like the iPad 3 and iPhone 4 before it, Apple would need to go to @2x (double the horizontal and vertical pixels) to increase the density.
The iPad mini is 7.87- x 5.3- x 0.28-inches and weighs 0.69 lbs. It currently uses the aforementioned 4:3 1024x768 (786,432 pixel), 163ppi screen, and gets 10-hours of battery life.
A theoretical iPad mini Retina would need to stick very close to those same size, weight, and battery life measures, but bump up the display to a 4:3 2048x1536 (3,145,728 pixel), 326ppi monster.
The Nexus 7 (2013) is 7.87- x 4.49- x 0.34 and weighs 0.64 lbs. It now uses a 16:10 1920x1200 (2,304,000 pixel), 323ppi screen, and gets 9-hours of battery life - in airplane mode.
So the Nexus 7 is a little thicker (though still light thanks to the plastic back), but more importantly, has only 3/4 of the amount of pixels an iPad mini Retina would need, and even then at only a fraction (who knows how much?) of the battery life. In other words, the Nexus 7 (2013) is thicker, has less pixels, and less battery life than a theoretical iPad mini Retina.
While impressive in its own rights, those still aren't the numbers, and certainly not the formula, Apple needs to hit.
Apple, I'm guessing, wants the same or similar thinness - technically lightness, but they use aluminum instead of plastic for the chassis so it needs to be thin to be light - from an iPad mini Retina as the original iPad mini, with four times as many pixels, and with the same battery life. And the devil most certainly is in those details.
There have been advances in LED backlighting, and in display technology, in systems-on-a-chip, and in operating system battery optimization that might let Apple hit all those measures. But they weren't in place last spring when the original iPad mini launched. Whether or not they are in place by this October, the same time this year that the original iPad mini launched last year, we'll have to wait and see. (That's perhaps the reason for the seemingly conflicting rumors of fall 2013 and spring 2014 releases - best possible and fall back windows.)
Much like the first Nexus 7 showed the small tablet form factor has potential, the second Nexus 7 shows the high density small tablet form factor has potential. It wasn't where Apple needed it to be before, but it's coming. Of that, have no doubt.