Google Pixel 2 XL vs Apple iPhone 7 Plus, Do We Need Dual Camera For Bokeh Effect in Portrait Mode?

In their official press release for the 2016 Apple iPhone 7 Plus - the first iPhone to have a Dual Camera Module at the back - Apple said,

"The Dual 12-megapixel cameras also enable a new depth-of-field effect, using both cameras on iPhone 7 Plus to capture images, while sophisticated technology including Machine Learning separates the background from the foreground to achieve amazing portraits once possible only with DSLR cameras." (source)

This effect implemented in the Portrait Mode of the handset is also called "Bokeh" where the background of the subject is beautifully or lusciously blurred to deliver a more interesting, focused, and beautiful shot.

Apple's patent application for the use of a secondary optic to achieve this effect explains how exactly the technology works:

"A second lens assembly, wherein obtaining a depth map of the scene comprises obtaining a depth map of the scene using the first lens assembly and the second lens assembly, wherein the first lens assembly and the second lens assembly are part of a stereo camera system. [...] A focal length of the first lens assembly is different than a focal length of the second lens assembly. [...] The computer code further configured to cause one or more processors to capture a preview image using the second image capture device concurrently to the capture of the plurality of frames."

Since the Apple iPhone 7 Plus currently delivers one of the - if not the - cleanest bokeh effect on portrait images taken using a smartphone, I believe many mobile consumers had become convinced that a Dual Camera module is indeed necessary to get decent shallow depth of field if you're just using a handset as a camera substitute.

However, I've always thought that it's not true at all. I mean, Apple's patent application makes sense and their works for them. But I don't think it's the only way that you can get bokeh on your shots if you're just using a cameraphone.

And this why I was delighted when I saw these sample shots taken using the Google Pixel 2 XL, which was officially announced - just five days ago - on October 4, 2017.

Google Pixel 2 and Pixel 2 XL both only have a singular optic camera module -- and yet they can deliver photos with good shallow depth of field effect. (Photo Credit: The Verge)

Just look at these portrait shots -- and take note, they were taken using a smartphone that only has  one 12 MegaPixel f/1.8 aperture at the back!

Photo Credit: Google Inc.

According to DxOMark - a website that measures smartphone camera quality, "Because the Pixel 2 has only a single main camera, software is what generates Zoom, Depth Effect, Portrait Mode, and Bokeh from one or more frames captured with that camera."

"Pixel 2 also bring you Portrait Mode. But we're implementing it a little bit differently. Other smartphones do this by combining images from two cameras. Pixel 2 does Portrait Mode with just one camera and Machine Learning. What's unique about Pixel 2 is that it can generate a True Depth Map with just a single lens so you get beautiful portrait shots without needing a second camera. The way this works is that the Portrait Camera includes a Dual Pixel sensor technology. This means that each pixel in an image contains a right and a left view. The difference in perspective from those pixels combined with machine learning models trained on almost a million photos means that this works on really hard cases like a busy colorful background. And yes, this does work on objects too," explained Mr. Mario Queiroz, Google's Vice President and General Manager for Pixel, on how the Pixel 2 and Pixel 2 XL's Portrait Mode works.

He added, "And there's more. Portrait Mode doesn't just work on the front camera. Because of the quality of Google's computational photography with a single camera, you can also take Portrait Selfies with the front camera on both the Pixel 2 and the Pixel 2 XL."

Impressive, right?

But here's the thing, despite declaring that the Google Pixel 2 and 2 XL have set "a new record for overall smartphone quality" and giving the cameraphones an unprecedented score of 98, DxOMark said that while the software on both models does a good job in mimicking shallow depth of field, the resulting images still have flaws. To specific, that said that "The feature is susceptible to irregularities from frame to frame, however, with occasional artifacts along the edges of subjects. Indoor scenes can also display gradient artifacts."

Looking at these comparison Portrait images taken using both Google Pixel 2 and Apple iPhone 7 Plus, though, I think the Pixel 2 still has superiority in clearing out the subject's edges, creating a more natural looking shot.

Credit: DXoMark

Let's zoom in on the subject.

Apple iPhone 7 Plus Portrait Mode

Google Pixel 2 Portrait Mode

Now, I don't know about you -- but for me, it's night and day. Pixel 2 wins in this case. Just look at how the edge of the subject's hair seamlessly blended with the background in the photo taken using Google's new handset.

So to wrap this up, I want to ask you, "Now that Google has shown that good bokeh effect can be achieved using just a single camera module, what other applications of a Dual Camera module will you be interested in seeing and experiencing on a smartphone?" Share you thoughts in our comments section below. We'd love to here your ideas so we can share them with handset manufacturers when we get the chance to talk to them.

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