Updated October 5th, 2020.
Many iPhones have a “Display Zoom” setting which enlarges everything on the screen. Not just text, but icons, controls, buttons, everything. It’s really great. That feature, which has been around for years, did not exist on the iPhone X, Xs, or 11 Pro until iOS 14 came out, and there’s a technical reason for that.
The technical reason is interesting, but knowing how to turn on Display Zoom is even more interesting, so we’ll start with that.
How to turn on Display Zoom
These instructions apply to many other iPhones too.
Go to Settings, then Display & Brightness, then scroll to the bottom of that page.
Remember, if you’re using an iPhone X, Xs, or 11 Pro, this only works if you’re on iOS 14. It won’t work in iOS 13 or older.
When you first look at the Display Zoom settings they’ll say “Standard.” Tap that and you’ll see three examples of how your iPhone would look with Zoomed turned on.
The samples show representations of the Home Screen icons, Notifications, and Messages. If you like the Zoomed version, tap Zoomed, then tap “Set” at upper right. Your iPhone will quickly restart and when it does, it will come back zoomed.
This is way better than just enlarging the text, because everything is bigger. Bigger icons and buttons are easier to tap. Bigger everything is easier to see. Bigger is better.
Why it works now
Now for the technical reason that the Zoom feature has magically appeared thanks to iOS 14. It has to do with why Zoom works in the first place.
Basically, iPhone screens are rectangular grids of pixels. Different iPhones have different screens, and thus different numbers of pixels. What Apple does, when you select “Zoomed,” is they treat your iPhone as if it’s a different model— one with a smaller screen, and fewer pixels. If you take the image that would have fit on a smaller screen, but you stretch it to fit a larger screen, everything is bigger. And that’s how Zoomed works.
This is a great scheme, but it only works if Apple has a smaller iPhone model with the same screen proportions as yours. For example, the iPhone 8 Plus and the iPhone 8 have the same screen proportions (1080 x 1920 on the 8 Plus, 750 x 1334 on the 8), so Apple displays an iPhone 8 image on an iPhone 8 Plus screen with no visible distortion, and of course everything is bigger. (Divide the height by the width on both phones and you get almost exactly the same ratio: 0.5625 for the 8 Plus, 0.5622 for the 8. Close enough.)
The iPhone 11 Pro Max has the same proportions as the iPhone 11 Pro (1242 x 2688 for the 11 Pro Max, 1125 x 2436 for the 11 Pro, 0.463 vs. 0.4618, close enough), so if you choose Zoomed on the 11 Pro Max, what you’re really seeing is an 11 Pro image stretched to fit an 11 Pro Max screen.
Every iPhone that has the Zoomed feature implements it the same way. Apple treats the iPhone as if it’s a smaller-screened iPhone model, and scales up the image to fill the bigger screen.
The iPhone X, Xs, and 11 Pro don’t have “little brother” iPhone models with the same proportions, so there’s no iPhone screen that Apple can scale up to fill the screens of the X, Xs, and 11 Pro. Thus, you’d think that Display Zoom would never exist… but now it does!
So what’s going on here?
What’s going on is, Apple knows about an iPhone model with the same screen proportions as the iPhone X, Xs, and 11 Pro, and they’ve given iOS 14 knowledge of it… even though that particular iPhone model hasn’t been released!
Which means that now we know there will be a new iPhone released, sometime during the life of iOS 14, with screen proportions similar to the X, the Xs, and the 11 Pro (all 1125 x 2436 screens, or 0.4618), but smaller. That iPhone’s screen is being stretched (virtually) to fit the bigger X, Xs, and 11 Pro screens– that’s why the Zoomed feature works now.