Display Zoom is a truly great feature for those that need it. The usual go-to accessibility setting for older people is the text size slider. However, I recommend turning to Display Zoom, and considering adjusting the text size as a last resort. Both accessibility features help people with poor eyesight, but the mechanics are very different.
With Dynamic Text, the OS uses larger font sizes for body text and some headings. Due to the limited available space, components like iOS toolbars use fixed metrics and do not change the text size of their buttons at all. When the system font size is increased significantly, this results in a pretty ugly mish-mash of application UIs with some parts of the screen being enlarged whilst other areas don’t change. Often, the app will change the text size of a button but the button’s container doesn’t get bigger in kind, so you see a lot of truncated text. It’s also possible to encounter app layouts that are entirely broken with Dynamic Text active, as developers sometimes forget to test every screen of their app under these conditions.
Display Zoom works by making the OS pretend that it is running on a device with a lower resolution screen, causing apps to render at that smaller size, and then scaling that up to fill the actual display of the device. This means the entire interface is rendered physically larger. Display Zoom came to iOS starting with the iPhone 6 but it originated on the Mac; the behaviour is identical to the scaled display options in macOS System Preferences, except the iPhone only presents you with one choice of alternate resolution.
The main advantage of Display Zoom is that it applies to the entire screen evenly, enlarging everything uniformly. Unlike Dynamic Text, there is no distortion of the relative size of interface elements. Text is easier to read, UI elements are easier to touch. This latter point is frequently the more useful aspect. I set my grandpa’s phone to use Zoomed mode primarily because it makes touch targets easier to press. The lesser scaled resolution usually means there are fewer things visible on screen at once, and the things that do remain are simply bigger. As far as his accessibility to using the phone is concerned, the dexterity of his fingers and unfamiliarity with touchscreens are far greater barriers than the impact of his ageing eyesight. For instance, Display Zoom makes it much easier for him to type on the software keyboard, as each key is about 25% larger in Zoomed view.
My general advice is to enable Display Zoom first. Then, consider bumping up the text if that is still necessary. With Display Zoom magnification in effect, the number of font size increases required may only be two or three notches away from the system default, which is far less disruptive to app layouts than compared to cranking it all the way up to the biggest size.
Display Zoom employs non-integer scaling, which means it causes some degree of blurriness. The visual artefacts are minor though, and someone who needs to use Display Zoom for accessibility reasons won’t be able to perceive it.
Display Zoom imposes no additional engineering effort on app developers. Apple achieves this by having each iPhone simulate a screen resolution of another model in the lineup, that has the same aspect ratio. Every app in the App Store supports Display Zoom automatically, because to the app it is the same as if it was running natively on a different iPhone, and of course developers have to ensure compatibility with all the various iPhone form factors as a matter of course.
For example, the Zoomed view on grandpa’s iPhone 8 renders as if it was a 4-inch iPhone SE, the iPhone 8 Plus emulates a iPhone 8 screen and on the iPhone 11 Pro Max, it matches the resolution of the iPhone 11 Pro.
A quirk of time is that the 5.8-inch iPhone X has never offered Display Zoom. Because the X was the start of a new line of 18:9 iPhones, Apple didn’t have a suitable resolution from a counterpart phone to draw upon. The lack of Display Zoom carried through to the iPhone XS and iPhone 11 Pro, which share the same screen specifications. Dynamic Text is available, but no Display Zoom.
This omission was an unfortunate downside of the modern non-Max iPhones. Hopefully, me extolling the benefits of Display Zoom across the last five paragraphs shows why that matters. The good news is that iOS 14 beta 3 adds Display Zoom to all 5.8-inch phones.
But what about the lack of smaller 18:9 iPhone? Apple hasn’t released any new sizes. Yet. As tested by 9to5Mac in the iOS Simulator, and as seen by taking a screenshot on the iPhone 11 Pro in Zoomed mode, the never-before-seen resolution is 960x2079 (or 320x693 at 3x scale). That’s the same width as the old 4-inch phones. Odds on, this is the resolution of the new 5.4-inch iPhone, which will be one of four iPhone 12 models coming this fall.
The introduction of a new resolution means Apple is facing yet another iPhone hardware cycle where users will have to wait a few months for developers to update their apps so they can fully enjoy their new phone’s form factor, free of top and bottom black bars. Apps will need to update to explicitly declare compatibility for this screen size. Otherwise, apps appear on-screen letterboxed. You can try this out for yourself; install beta 3 on a 5.8-inch iPhone, enable Display Zoom, and launch any App Store app.
It’s funny that Apple slipped this in during the third beta seed, as if no one would notice. They would have probably been better off shipping it as part of beta 1 and drawing attention to it in a WWDC session, proudly touting the addition of Display Zoom to the 5.8-inch phones as a new feature. We would always make the connection to the rumoured new phone size, but you might as well start evangelising apps to support it as soon as possible.
All of Apple’s system apps are already updated to fill the screen. I spent a good twenty minutes using my phone in Zoomed mode to get a feel for what the forthcoming 5.4-inch phone might be like to use day-to-day. It seemed fine. I could not find a single place in the system where I found the smaller screen real estate meaningfully lacking. I didn’t feel like I was missing out on something. If you are yearning for the smaller-phone-with-premium-specs, I think you’ll be happy with what you are getting. The loss in horizontal resolution is not a big deal; some controls like tab bars just have less whitespace between the buttons.