Apple Watch Sport's Display With Ion-X Glass Outperforms Sapphire Models in Bright Lighting

Although there has been much comparison of the scratch-resistance and weight differences between the two Apple Watch display cover options -- sapphire crystal and Ion-X glass -- not much has been scientifically tested regarding each model's reflectiveness. A new report by DisplayMate out today, however, shows just how much lower reflectivity and higher contrast there is on the Apple Watch Sport's Ion-X glass compared to the higher-end Apple Watch models with sapphire.

As DisplayMate points out, the two models have identical OLED displays internally, but thanks to the different outer coverings, the different models react uniquely in bright light situations. In summary, the site found that the Apple Watch with sapphire crystal display reflects 74 percent more ambient light than the Ion-X glass of the Sport model. The two displays behave almost identically in dark environments given the low levels of ambient light available for reflection.

DisplayMate_Photo_28_800

Photo comparing Ion-X glass (left) and sapphire crystal (right) taken at 2,000 lux, which equates to moderate outdoor lighting

For the Apple Watch Sport with Ion-X Glass we measured the Screen Reflectance to be 4.7 percent, while for the Apple Watch with Sapphire we measured 8.2 percent Screen Reflectance, which is 74 percent higher than with Glass. Both values are about 0.6 percent higher than just pure sapphire and glass alone, indicating that Apple has done an excellent job in optically bonding both the glass and sapphire to the OLED display without an air gap.

The 74 percent higher Reflectance of the Apple Watch with Sapphire means that its screen will reflect almost twice as much surrounding ambient light as the Apple Watch Sport with Glass. And it takes surprisingly little ambient light for that to make a significant visible difference…

Starting in the dark at 0 lux, DisplayMate increased light levels in successive stages of testing to discover the contrast ratios of each screen under increasingly stressful lighting situations. With both displays set to their maximum brightness, at 500 lux ("mid-range indoor ambient lighting") the display contrast ratios had fallen from 100 to 64 for Ion-X and 38 for sapphire, illustrating the distinct visibility advantage for the cheaper model. Jumping to 2,000 lux ("moderate outdoor lighting in the shade or an overcast sky"), the ratios drop to 17 and 10 for Ion-X glass and sapphire, respectively.

Screen Shot 2015-06-29 at 11.16.08 AM

Chart comparing various aspects of reflectivity between the two displays

For a full-on sunlight measurement of 10,000 lux, the Ion-X glass display contrast ratio fell to 3 while the Sapphire Crystal came in at just 2. So, while the Sport's display proves to handle moderate outdoor sunlight much better than the sapphire display, both are significantly impacted by harsh, direct sunlight.

Higher reflectivity and lower light transmittance were highlighted as challenges for Apple amid Apple's failed partnership with GT Advanced Technologies for sapphire production and rumors the iPhone 6 would include a sapphire display cover. Recent advancements in sapphire production technology may, however, overcome those difficulties, with future generations of products able to use sapphire that has better viewing characteristics than glass while retaining sapphire's advantages of high scratch resistance.

Related Roundup: Apple Watch 10
Buyer's Guide: Apple Watch (Neutral)

Popular Stories

AirPods Pro 3 Mock Feature

AirPods Pro 3 Just Months Away – Here's What We Know

Friday April 18, 2025 5:16 am PDT by
Despite being more than two years old, Apple's AirPods Pro 2 still dominate the premium wireless‑earbud space, thanks to a potent mix of top‑tier audio, class‑leading noise cancellation, and Apple's habit of delivering major new features through software updates. With AirPods Pro 3 widely expected to arrive in 2025, prospective buyers now face a familiar dilemma: snap up the proven...
iphone 16 pro models 1

17 Reasons to Wait for the iPhone 17

Thursday April 17, 2025 4:12 am PDT by
Apple's iPhone development roadmap runs several years into the future and the company is continually working with suppliers on several successive iPhone models simultaneously, which is why we often get rumored features months ahead of launch. The iPhone 17 series is no different, and we already have a good idea of what to expect from Apple's 2025 smartphone lineup. If you skipped the iPhone...
Beyond iPhone 13 Better Triad

Apple's 20th Anniversary iPhone May Finally Go All Screen

Tuesday April 15, 2025 6:31 am PDT by
Apple is preparing a "bold" new iPhone Pro model for the iPhone's 20th anniversary in 2027, according to Bloomberg's Mark Gurman. As part of what's being described as a "major shake-up," Apple is said to be developing a design that makes more extensive use of glass – and this could point directly to the display itself. Here's the case for Apple releasing a truly all-screen iPhone with no...
maxresdefault

iPhone 17 Pro Launching Later This Year With These 12 New Features

Sunday April 13, 2025 7:52 am PDT by
While the iPhone 17 Pro and iPhone 17 Pro Max are not expected to launch until September, there are already plenty of rumors about the devices. Subscribe to the MacRumors YouTube channel for more videos. Below, we recap key changes rumored for the iPhone 17 Pro models as of April 2025: Aluminum frame: iPhone 17 Pro models are rumored to have an aluminum frame, whereas the iPhone 15 Pro and ...
CarPlay Hero

Apple Releases Wireless CarPlay Fix

Wednesday April 16, 2025 11:28 am PDT by
If you have been experiencing issues with wireless CarPlay in your vehicle lately, it was likely due to a software bug that has now been fixed. Apple released iOS 18.4.1 today, and the update's release notes say it "addresses a rare issue that prevents wireless CarPlay connection in certain vehicles." If wireless CarPlay was acting up for you, updating your iPhone to iOS 18.4.1 should...
iOS 18

iOS 18.5 Includes Only a Few Changes So Far

Monday April 21, 2025 11:00 am PDT by
Apple seeded the third beta of iOS 18.5 to developers today, and so far the software update includes only a few minor changes. The changes are in the Mail and Settings apps. In the Mail app, you can now easily turn off contact photos directly within the app, by tapping on the circle with three dots in the top-right corner. In the Settings app, AppleCare+ coverage information is more...
top stories 2025 04 19

Top Stories: iPhone 17 Pro Rumors, CarPlay Bug Fix, and More

Saturday April 19, 2025 6:00 am PDT by
This week saw rumor updates on the iPhone 17 Pro and next-generation Vision Pro, while a minor iOS 18.4.1 update delivered not just security fixes but also a fix for some CarPlay issues. We also looked ahead at what else is in Apple's pipeline for the rest of 2025 and even the 20th-anniversary iPhone coming in 2027, so read on below for all the details on these stories and more! iPhone 17 ...
ipad air windows 11 arm

M2 iPad Air Runs Windows 11 ARM via Emulation, Thanks to EU Rules

Tuesday April 22, 2025 5:01 am PDT by
A developer has demonstrated Windows 11 ARM running on an M2 iPad Air using emulation, which has become much easier since the EU's Digital Markets Act (DMA) regulations came into effect. As spotted by Windows Latest, NTDev shared an instance of the emulation on social media and posted a video on YouTube (embedded below) demonstrating it in action. The achievement relies on new EU regulatory...

Top Rated Comments

penajmz Avatar
128 months ago
Let the whining BEGIN!
Score: 11 Votes (Like | Disagree)
jabingla2810 Avatar
128 months ago
The clarity from the lack of reflection will be negated by all them scratches! :p
Score: 11 Votes (Like | Disagree)
Z400Racer37 Avatar
128 months ago
WORKAROUND: Don't aim watch face at the sun.
Score: 11 Votes (Like | Disagree)
dumastudetto Avatar
128 months ago
My Apple Watch Edition has the same problem in bright sunlight. It's annoying, but overall I value the social status I acquired with my purchase more than worrying about trying to use it.
Score: 11 Votes (Like | Disagree)
Col4bin Avatar
128 months ago
IF I were considering purchasing and Apple Watch, I'd naturally go for the Sport model… but only based on it's lower price point. (The better on-screen contrast with the Ion-X glass is an added bonus.)
Score: 9 Votes (Like | Disagree)
Quu Avatar
128 months ago
My Apple Watch Edition has the same problem in bright sunlight. It's annoying, but overall I value the social status I acquired with my purchase more than worrying about trying to use it.
lol
Score: 9 Votes (Like | Disagree)