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Thursday, November 3, 2016

iPhone 7 Plus vs. Google Pixel XL

The Google Pixel XL excels at mobile phone photography, edging out Apple's iPhone 7 Plus With video, though, it's a different story.


My colleague Vanessa Hand Orellana and I spent hours chasing pigeons, children, dogs and sunsets to put the two cameras to the test. The Pixel XL had its moments, but on the whole, we agreed the iPhone 7 Plus captured better video.
Its biggest advantages were color, image stabilization, sharpness, contrast, low-light shooting and zoom, unsurprisingly given its second camera.
The Pixel XL, which offers the identical cameras and image processing as the Pixel, did lead the iPhone 7 Plus in some areas, though. Its autofocus was faster, and it sometimes kept a nice exposure when the iPhone went overboard with brightness. Google's phone handily beat the iPhone 7 Plus when it came to slow-motion video with sharper imagery, too.
When Apple debuted the first iPhone in 2007, it couldn't shoot video at all. That's unthinkable today even for a low-end phone. Good mobile video is crucial in the era of YouTube, Facebook and Snapchat. Even if you're not into sharing, video is key to chronicling our lives. So it behooves you to pay attention to video quality.
Don't consider this a final judgment. Much of Google's approach to photography and videography involves extensive image processing, including its excellent HDR+ technology used for photos. There's no HDR+ for video, but Google still could offer camera app software updates to address some Pixel shortcomings.
Here's a look at some of the details of our tests.

Image stabilization

The two phones take a very different approach to image stabilization, a critical aspect of video quality. The iPhone 7 Plus uses an optical approach that physically moves lens elements to counteract the camera motion caused by shaky hands or movement when you're walking. The Pixel XL uses digital stabilization, which uses motion sensors and image data to try to mathematically compensate for camera movement.
Each has its advantages when it comes to camera size, component costs and other factors, but we found the iPhone's approach generally resulted in a smoother, more human feel. The Pixel XL would try hard to stabilize a shot, but when it figured out you really had pointed the camera in a new direction, there would be an abrupt stop-and-start shift to the new perspective. This made video jerky. The iPhone wasn't as good at compensating for the bobbing perspective you'll often see in videos shot while walking, but it still looked more natural.
And likely because the Pixel XL relies on its processor for stabilization, it struggled when shooting video at 60 frames per second -- double the rate of ordinary 1080p video and thus double the number of pixels to process -- or when shooting higher-resolution 4K video at 30 frames per second.
Video from the Google Pixel, left, handled overexposure challenges with more natural look than the Apple iPhone 7 Plus.
iPhone 7 Plus videos at times were overexposed, a problem I've found in iPhone photos, too, where foreheads and cheeks in the sun are glaring white, orange or yellow. In dim conditions, details in shadowy areas often disappeared into the murk. The Pixel XL handled exposure better overall, though I preferred the iPhone 7 Plus with sunrises and sunsets that are a challenge for any camera today.
The Pixel XL gets a big demerit in one area of exposure, though. When I shot while walking, sometimes the exposure would pulse darker with each footfall. This happened in several videos.
Color

The iPhone generally selected more pleasing, warm tones. In good lighting conditions both cameras were reasonable, but I found the iPhone 7 Plus colors to be vibrant while still natural -- perhaps a result of the wider P3 color gamut it uses compared to the Pixel XL's more limited sRGB range of colors.
​The iPhone 7 Plus video, top, wasn't quite as sharp in this shot, but color was more natural than the Pixel's, and its wider-aperture lens gave a nicer background blur.

Sometimes skin tones with the Pixel XL video had a yellowish cast. I think of this as the "putty effect." Under warm-hued indoor light, the Pixel XL showed people as too orange. It could switch color settings rapidly, too, in one case switching back and forth distractingly between an orange and blue tint.

Sharpness

Here the iPhone won, perhaps a result of its six-element lens design or better image processing technology that creates the video from the raw image-sensor data. The Pixel XL was usually adequate, but with videos of subjects like city skylines and nature landscapes, the edges on the iPhone were crisp without appearing over sharpened.
The Pixel XL was sharper taking slow-motion video, though. We shot at 240 frames per second, a speedup factor of 8 compared to regular video. Both the Pixel XL and iPhone 7 Plus can only shoot at 720p resolution, which is fine but not as sharp as full high-definition video at 1080p.
Of course, if you want to zoom, the iPhone 7 Plus has dual cameras -- 28mm and 56mm equivalent focal lengths -- and the 2X setup is much better for portraits, kids who aren't in front of you, concerts and many other situations with distant subjects. But there's a big caveat: there's no optical image stabilization for the 56mm camera. Because of that, and a lens that doesn't let in as much light, the iPhone 7 Plus uses the wider-angle camera in dim conditions, making it just like a plain old single-camera iPhone 7.
​Lens flare troubled both cameras when shooting toward the sun. The Pixel, left, showed a distracting ring but didn't wash out bright areas as much.

Lens flare
Both cameras suffered from lens flare, the streaked and washed-out areas that result from shooting toward the sun or other bright light sources. The Pixel XL sometimes would produce a ring around the sun even when the sun was outside the frame -- the Pixel XL "halo effect" that Google hopes to easewith better processing at least in photos. The iPhone 7 Plus would wash out details nearer the sun and add a green ghost image of the sun diametrically across the frame from the sun. I was disappointed in both cameras, frankly, but the edge goes to the Pixel XL for better contrast and less haze when shooting directly toward the sun.

Autofocus

I enjoyed the Pixel XL's snappy autofocus, especially its ability to lock in more quickly on close-up subjects. It also did better locking focus during slo-mo shooting, where you're more likely to notice a longer wait.
​The Pixel produced brighter nighttime video, but it suffered dramatically from smeary noise-reduction artifacts.

Low-light conditions
I had high hopes for the Pixel XL, whose pixels are 60 percent larger than the iPhone 7 Plus' and therefore in principle are better able to shoot in dim conditions where photons are scarce. Instead, the iPhone gave the Pixel XL a drubbing. iPhone video suffered from the transient jittering of noise speckles, but the edges were sharp, and the noise was far less distracting than the Pixel's crude, smeary noise reduction. Both cameras struggled at times to catch focus, a common affliction in the dark. When shooting indoors, the iPhone again showed superior performance, though in smaller rooms, the Pixel XL's wider-angle field of view is a big advantage.

Front camera

​The iPhone 7 Plus front-facing camera exposed better than the Google Pixel's at times.
The Pixel XL did a nice job exposing faces and keeping focus, but it sometimes struggled with backlit faces, choosing to silhouette me. Sometimes it underexposed even without silhouettes. I liked its sharpness better, but overall the iPhone did a better job with skin tones and showed a more lifelike degree of contrast.

4K video

For this higher-resolution format, the Pixel XL was nicely exposed, but the iPhone 7 Plus outdid it when it comes to sharpness. And why bother shooting 4K video if you're not paying attention to sharpness? Again, the iPhone's optical image stabilization was more natural. On the Pixel XL, I spotted some compression artifacts in even-toned areas, a blue sky and a red ceiling.
Overall, it's an iPhone victory for video. Perhaps we'll see a software update from Google that will help it catch up.

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