A closer look at iPhone XS Max’s Depth Control feature

Updated on 04-Jun-2020
HIGHLIGHTS

Apple set some high expectations with the camera on the iPhone XS Max. We take a closer look at what the hype is all about.

At the iPhone launch event this year, Apple set some high expectations for the camera of the iPhone XS and the iPhone XS Max. Phil Schiller, Apple’s Senior Vice President of Marketing took to the stage and claimed, the camera on the iPhone is the “world’s most popular”. He ran through slides showing what people have done with the iPhone’s camera over the past ten years, not just the average joe, but also professionals. In fact, Apple said the cover photo of Time Magazine’s September issue was shot using the iPhone. Now, like every year, Schiller also claimed the camera on the iPhone XS and the iPhone XS max are the best Apple has ever made. Best in what way, you may ask? Well, Schiller said the camera team studied “some of the highest-end full-frame cameras and expensive fast lenses to characterize the quality of professional bokeh and bring that capability to more and more of us through the portrait mode photos taken with the iPhone.”   

The feature is called Depth Control and it lets you adjust the amount of background blur in portrait shots. The iPhone XS camera has a slider in post-processing that adjust the background blur by simulating multiple apertures. It’s not a feature that’s new, though. It has been there in Android phones for quite some time now. Nevertheless, it’s always good to have more tools to play around with.

Apple does this using the AI chops of the A12 Bionic processor along with using a better sensor and the secondary telephoto lens. Schiller namechecked computational photography (a term Google likes to use very much for its Pixel phones), and the on-stage demonstration of the feature a lot of “noo” and “oohs” from the crowd. Clearly, Apple fanboys were left impressed. So was I. And when the iPhone XS Max landed up in our hands for review, I took the phone out for a spin especially to see for myself what the hype is all about.

To see just how effective the feature is, we took photos from the iPhone XS Max and the Honor 10, to put things in perspective. While Android phones have had the feature for a while, the implementation is what matters. Who wins? Let’s find out.

These are the sample shots I used to compare:

Test Subject 1:

(Left: iPhone XS Max, Right: Honor 10)

 

Facial Details

Both phones aren’t bad at blooming a bokeh in the background. Only, the iPhone’s looks so much better. The photo from the iPhone was shot using the telephoto lens, so the subject appears much closer than the Honor 10. More than that, the details on the face is so much apparent in the first sample. You can make out the sweat beads as well as the gradual change in skin tone from the bright to dark parts. In comparison, the Honor’s 10 portrait looks smoothened out, especially in the forehead region, where the iPhone manages to capture a lot of details. Both phones can handle the spectacles quite well though, which many phones find difficult to implement. Quite clearly, the iPhone XS Max is doing a better job here.

Test Subject 2:

(Left: iPhone XS Max, Right: Honor 10)

Edge Separation

This is where the iPhone XS Max struggles a bit. While the details inside the focus area are near about perfectly preserved, it’s the edges that make the phone falter a bit. By looking at the edges, you can easily make out this is a result of artificial algorithms and not physics. Notice the hair on the photo taken on the iPhone XS Max. The right edge of the hair is sharp like it was cut out using Photoshop. The phone also creates a shadow layer on top of the head that looks like a black halo. In comparison, the Honor 10’s portrait has cleaner edges. It’s not perfect either and also seems to be done on a computer, but this one looks more natural.

Test Subject 3:

Background Blur

Now let’s focus on the background. In both cases, the background is tad overexposed, but that’s bound to happen considering the limited scope for dynamic range on smartphone imaging sensors. But let’s look at the details. The Honor 10’s blurring of the background clearly shows circular highlights, however, the round artefacts seem to be artificial. The leaves have turned circular, which shouldn’t be the case under natural light. On the other hand, the iPhone XS Max nails it with the bloom. The portrait in this case is shot at a simulated aperture of f/1.8. It’s difficult to make out what the background is composed of, which is what one would want from a bokeh shot — total focus on the subject with no distraction from the background. That doesn’t seem to be the case in the photo taken on the Honor 10. There you can make out almost every element in the background, only it seems like you’re looking without your spectacles.

In this subject too, the edges look more artificial. The iPhone struggled to find where the hair ends and botches it up by blurring parts of the hair around the edges. The Honor 10 too had similar difficulties. Further, the details are a lot more apparent on the portrait from the iPhone XS Max. The Honor 10 simply whitewashes everything and applies a smoothening filter to make it look good.

The Implementation

via GIPHY

 

The depth control on the iPhone XS Max running iOS 12 can be accessed after you’ve taken the portrait photo. You can tap on the ‘Edit’ option in a portrait mode photo and you’ll see a slider with multiple f-stops pop up. Taking the slider to the left increases the depth of field while taking it further to the right makes it shallow. As the aperture gets bigger, the background bokeh increases and vice versa. It’s the same with the Honor 10 which has a dedicated aperture mode right in the viewfinder, apart from a similar option in post-processing. Here too you can adjust the bokeh according to aperture stops.

What’s interesting is the way the bokeh blooms on the iPhone XS Max as compared to the Honor 10. You can see the change in real-time as you slide and just like how it works on professional cameras, the foreground-background separation becomes clear when the aperture is larger. The bokeh is applied in the manner of a gradient with the farthest object blurred the most, while things closest to the subject can still be made out.

On the Honor 10, you only see the change after you’ve decided which aperture to stop the slider at. Secondly, there’s no gradient effect and the bokeh is applied uniformly no matter how far the background is. That’s what makes the Honor 10’s portrait look artificial while that of the iPhone XS Max looks much more natural, although it’s nowhere close to what it should be.

The bottomline

By examining this feature alone, it’s apparent that the iPhone XS Max indeed can do depth control better than its Android counterparts. It’s intuitive and the bokeh simulation looks very much like that from a professional camera. However, it’s restrained by physics. Professional cameras have a lot of space to play around with. There are multiple elements in the lenses and the aperture can be physically adjusted to create the perfectly shaped bokeh. While the iPhone’s is the closest we have seen on a smartphone, it’s still a work in progress. Doesn’t mean it’s bad though. In fact, we are pitting the iPhone XS’ camera against the likes of the Samsung Galaxy Note 9 and the Google Pixel 2 to see just how good the “world’s most popular camera” is.

You can check out more images taken by adjust the depth control on the iPhone XS Max in the Flickr gallery embedded below:

Subhrojit Mallick

Eats smartphones for breakfast.

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