The two lenses on the iPhone X are used for a few different tasks including optical zoom and portrait mode. By creating a depth map with both the cameras and identifying the subject, software then blurs out the background to simulate bokeh, or the shallow depth of field effect often associated with dSLRs.
The Pixel relies on just one lens to create this bokeh effect. Google's machine learning identifies what the subject in the photo is and keeps it sharp while blurring everything else.
On default settings the iPhone X makes colors pop, but compared with the Pixel 2, they can look more saturated.
The Pixel's colors are a bit more muted by comparison.
The iPhone also performs well in low light although the exposure on the blue background is a little brighter than the Pixel.
In low light, the Pixel retains detail and keeps images sharp.
Here's a photo taken on the iPhone X with auto HDR active (it's on by default). Compare it to the next slide from the Pixel.
Google's HDR+ Enhanced mode makes photos look more vivid than the regular HDR+ mode.
The iPhone often struggled to lock on and maintain portrait mode in extreme low light, while the Pixel grabbed the shot every time.
A photo taken on the Pixel with default settings.
A photo take on the iPhone with default settings on the wide-angle lens.
Portrait mode even works on still objects like flowers. On the iPhone, the blur effect is more subtle around the edges of the subject.
On the Pixel, portrait mode makes the subject really pop as it appears very sharp compared to the background.
Another example of how the Pixel keeps the subject sharp and the background blurred.
Portrait mode on the iPhone is more subtle, with the transition between sharp subject and blurred background.
The optical zoom on the iPhone means images in daylight are sharp whether you look at them at reduced magnification or at 100 percent magnification.
The Pixel relies on digital zoom to get you closer to the subject. At a reduced magnification you can't really see much difference between this and the iPhone's shot, but if you go in closer to 100 percent magnification, detail is smudgy.
Portrait mode works on fish, too. Shot on the Pixel 2.