Published On: Tue, Oct 3rd, 2017

Technology: Understanding the dual camera systems on smartphones

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Dual camera systems on smartphones have been around for several years now. Some of the earliest examples include the weird 3D camera on the HTC EVO 3D. Then it was HTC again who introduced it in a different form on the One m8. Then LG decided to drop in with its cool wide-angle lens with the G5 and the same year, Apple decided to take in the other direction by adding a telephoto lens on the iPhone 7 Plus. Meanwhile, Huawei had other ideas, with its Leica branded monochrome camera on the P9.

But just how many types of dual camera systems are out there and how do they differ from each other? Most importantly, are they any good or is it just a passing fad? Let’s find out.

The Depth Sensor

We will start with this as this is the most basic form of dual camera system. In this system, the primary camera is accompanied by a second camera whose only function is to 3D map the area in front of the camera. As you may know, we are able to see in 3D because we have two eyes with slightly different perspectives that help us convey depth, especially for things that are close to us.

The HTC One m8

The secondary camera in this system works similarly. With the second camera, the system can now tell roughly how far the objects in front of it are with respect to each other. This information is then used to separate the foreground subject from the background.

The most common use of this technique is to create a shallow depth of field effect. While it’s something that comes naturally to DSLR cameras with their big sensors and big lenses, the small smartphone cameras cannot achieve the same shallow depth of field. So instead, this technique is used to first figure out the borders of the foreground subject and then apply an iris blur effect on everything else. This gives the illusion of shallow depth of field.

Sample from the HTC One m8. Didn’t always work this well.

While sound in theory and occasionally in practice, this technique has its pitfalls. Unless your subject is a cardboard cutout, it will have depth to it and because this depth is not as much as the depth between the entire subject and the background, the camera occasionally ends up blurring the edges of the subject as well. Even when it does work reasonably well, it never quite looks natural, especially since most smartphone cameras that have this feature apply an even blur on everything in the background whereas with a DSLR, the intensity of the blur increases with the distance from the focus point.

Camera systems with a dedicated depth sensor is one of the rarest types of dual camera systems. The first popular use of it was seen on the HTC One m8 but these days only the most basic smartphones, such as the Honor 6X or the Lenovo K8 Plus, can be seen using a dedicated depth sensor lens.

The Monochrome Camera

A slightly more popular implementation of the secondary sensor is the monochrome camera. In this method, the primary camera is accompanied by a mostly identical secondary camera. Both cameras usually have identical sensors, apertures, lenses and focusing systems. The main and usually only difference between the two is that the second sensor lacks an RGB color filter. This means that the sensor cannot capture color information but on the upside, because there is one less thing blocking the sensor, the monochrome camera can capture more light.

Huawei P9

About the Author

- A graduate of Computer Science, Currently the Concept Designer of Vision Inspired Ventures owners of Online Magazine oshodioke,com. Nasbanky is a Creative Writer, a professional Social Media Optimizer, Graphic Artist, Photographer, Fashionista and Event Consultant . Find me on Social Media Nas Banky or Call 08035554812

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