Smart HDR is like regular HDR, only smarter. Smart HDR first appeared on 2018’s iPhone XS, iPhone XS Max and iPhone XR. It takes full advantage of the advanced camera sensors, the power of the A12 Bionic chip’s Neural engine, machine learning, artificial intelligence, computer vision and the latest computational photography advancements. With Smart HDR, all iPhone photographers can effortlessly take beautifully-lit photos with great dynamic range.
You just press the shutter button and your iPhone does the rest. Behind it, however, is immense technology that takes full advantage of the Apple-designed CPU, GPU and ISP, pairing these with a software camera stack so you can take beautiful pictures with little or no effort at all.
Smart HDR brings better color, plus more highlight and shadow detail to your photos
Compared with the normal and Auto HDR modes on earlier iPhones, the Smart HDR feature made its debut on the iPhone XS series and is unavailable on older models that lack faster sensors, zero shutter lag and other advancements. With Auto HDR, you can basically freeze a moment in time with more detail than ever before and make sharper action shots a reality.
Follow along for the full explainer.
HDR crash course
HDR stands for High Dynamic Range.
It’s a digital photography technique that helps take great shots in high-contrast scenarios. HDR does the compositing and tone-mapping of images to extend their dynamic range beyond the native capability of your capturing device. It works best when photographing a shaded subject, like your kid, set against a bright background such as a sunny sky.
Only HDR makes shots like this possible: great low‑light detail, no blown-out sky
With traditional DSLR cameras, you must choose between a sky that’s too bright or a subject that’s lost in the dark. With HDR, you get the best of both. When HDR is on, an iOS device’s camera takes three photos in a quick succession, each at a different exposure level: one at normal exposure, then one each of the brightest and darkest parts of the scene.
The best parts of each exposure are merged into a single shot with higher dynamic range. As such, HDR is especially useful in difficult lighting conditions, like harsh backlighting.
The images below provide the perfect example for how the HDR features work.
At left, you see an image taken with an exposure that’s balanced for the subject, which results in a sky that’s overexposed or too bright. The rightmost image was taken using an exposure balanced for the sky, which has made the subject underexposed or too dark.
HDR blends three shots to improve detail in the bright and midtone areas
As you can see for yourself, HDR took the best parts of the overexposed and underexposed shots and merged them with a third shot taken at a normal exposure, resulting in a detailed photo (the middle) with great contrast and detail.
And thanks to Apple’s sophisticated wider-gamut screens and cameras that support taking wide color photos and displaying them on your iPhone or iPad (the P3 Display profile), you’ll see up to 60 percent greater dynamic range in your HDR shots.
Auto HDR on iPhone X
On iPhone X and newer, HDR is on auto-pilot.
iPhone X and later use HDR for both their rear and front-facing cameras when it’s most effective, but you can disable this behavior by toggling off Auto HDR off in camera settings.
iPhone X and up automatically use HDR when appropriate
As we mentioned earlier, devices like iPhone XS, iPhone XS Max and iPhone XR feature improved camera sensors and chips that power HDR improvements.
Taking full advantage of these new cameras, Apple’s developed an even more advanced version of Auto HDR—and they aren’t calling it Smart HDR for nothing.
Say hello to Smart HDR
Smart HDR defaults to triggering any time it’s needed to improve image quality given the shooting conditions. Unlike the previous HDR modes, Smart HDR works with more types of photos that previously could not use HDR, like Portrait and Portrait Lighting modes, panoramic shots, bursts, frames in Live Photos and action shots like this one.
The Smart HDR feature is so well-implemented that nearly every image shot on an iPhone XS/Max/Xr takes advantage of it. It’s also interesting that all HDR images taken with an iPhone X or older are marked with “HDR” in the corner. On iPhone XS and up, however, Smart HDR is basically applied to all shots but the “HDR” badge is only displayed when it’s really extreme.
Daring Fireball’s John Gruber took a great iPhone XS vs. iPhone X comparison shot that I think best exemplifies HDR imaging improvements that the faster sensors, better chips and improved algorithms in these new iPhones allow for.
The difference speaks for itself.
The iPhone X image is clearly blown out whereas the one take with Gruber’s iPhone XS looks pretty good, which is entirely attributable to Smart HDR. “Notice too how in the XS shot you can easily read the ‘Shelton Theater’ sign in the back of the clown’s mouth,” Gruber writes.
You can disable Smart HDR in your camera settings to take non-HDR pictures every time you tap the shutter button in the Camera app. To manually control HDR:
- iPhone XS, iPhone XS Max & iPhone Xr: Turn off Smart HDR in Settings → Camera.
- iPhone X, iPhone 8 & iPhone 8 Plus: Turn off Auto HDR in Settings → Camera.
- Older models: Turn off HDR in Settings → Camera.
On all iPhones that support HDR imaging, the feature can also be managed at will in the Camera app, no need to visit Settings: just tap HDR at the top, then choose On or Off.
All iPhones before 2017’s iPhone X series always save a normally-exposed image in the Photos app alongside its HDR counterpart. That’s because HDR on those models is still a bit hit and miss. Needless to say, saving both HDR and non-HDR versions effectively doubles the storage space used for each HDR shot you take.
If you’d like to save space, save only the HDR version and discard any non-HDR variants. To do so, venture to Settings → Camera and turn on Keep Normal Photo. The most recent iPhones with more advanced sensors and chips, like the iPhone XS series and up, do not default to keeping a normally-exposed image alongside its HDR version at all.
And that’s all you need to know about HDR on iPhone.