Multiple Cameras in a Smartphone. Do you really need them?
Nowadays, almost every smartphone comes with at least three cameras baked right into it. It includes two rear cameras and one front-facing camera. The mid-range segment smartphone camera system may comprise up to 5 cameras (including front-facing camera). But, do these numbers really matter? What’s the purpose of numerous cameras? And, where it all started?

The Beginning

In 2011, LG Optimus 3D and HTC Evo 3D featured 5 Megapixel dual rear cameras which were meant to make your photos look real by adding depth to them. At that time, new 3D technologies were becoming popular in the world of cinema and the smartphone manufacturers decided to roll the dice by experimenting with a camera system which boasted a 3D experience but apparently, it proved to be a foundational step in the smartphone industry which is heavily adopted by everyone nowadays.

A typical smartphone nowadays may consist of a main/primary camera, a depth-sensing camera, a wide-angle camera, a macro-camera and probably a telephoto lens or a time of flight sensor depending on the budget of your smartphone. Okay, so what do they do?

Primary Camera

The primary camera of your smartphone is the default camera which is used more often than any other camera. It has the highest resolution, more megapixel count and probably image stabilization baked into it.

The primary camera consists of a lens with fixed focal length and an image sensor which you can say is the heart of the camera. The bigger the image sensor, the higher the image quality. High megapixel count doesn’t always mean better image quality. It depends on the size of the sensor as well as the quality of the sensor. There are a lot of other factors which affect the image quality, which we will talk about in a minute.

The primary camera has a standard focal length ranging from 24mm to 28mm. The camera lenses which have low focal lengths can capture a wider area like a landscape. As the focal length increases the field of view generally decreases.

One thing to note here is that the focal lengths mentioned here are not actual focal lengths of a smartphone camera lens.

In the world of smartphone photography, whenever you see a focal length of let’s say 26mm, that would be the focal length of a professional camera lens if it were to produce an image equivalent to the image captured by the smartphone from a particular angle.

Source: Realme

Depth-sensing Camera

As the name suggests, a depth sensor usually gathers information about the foreground and background of an image and uses that information to blur the background from the foreground of an image.

Why are they not used more often nowadays? Well, because most of the job is done by ‘software’ itself.

Wide-Angle Camera

The focal length of a wide angle lens in a wide angle camera is around 22–25mm which is less than the primary lens. A short focal length means a large field of view.

The purpose of this camera is to usually take landscape photographs or in smartphone terminology, wide angle photographs.

Normally they perform well but the overall image quality is slightly less than the primary camera.

Telephoto Camera

Telephoto camera has a different type of lens whose focal length is pretty long which eventually leads to a shorter field of view. What this means is that if you have an object far far away, you can capture the details of that object by using a telephoto lens.

In simple terms, it is used for zooming in an object without the help of digital zoom.

Nowadays, smartphone manufacturers use something known as ‘hybrid zoom’ which combines the image from a telephoto lens and further applies a digital zoom to zoom into an object even farther.

Macro Camera

A macro camera is generally used to capture tiny objects and minute details. The megapixel count of macro cameras in smartphones is usually low.

LiDAR Camera

You might have heard of a LiDAR sensor in the latest iPhone model but what’s the use of such a type of sensor? Well, the reason is quite interesting.

LiDAR (Light Detection and Ranging) is a technique in which the camera will fire pulses of infrared light on an object and will measure the time taken by the light to reflect from the object back to the camera sensor. In doing so, the distance of the object from the camera sensor can be calculated.

Also, by firing pulses of infrared light on multiple objects in a scene, the relative distance between those objects can be calculated which can be further used to know the depth information of those objects.

By doing so, you can blur the objects in the background from the objects in the foreground much more precisely and accurately rather than just guessing and approximating the whole thing.

LiDAR sensors can also be used for improving Augmented Reality in smartphones.

The availability of extra space in a smartphone is a big concern. You can’t have a lens which can change its focal length as per your requirement just like a DSLR camera. That’s why multiple lenses of different focal lengths are used to allow people to take shots from different angles.

We are in the era of smartphone photography. Nearly everyone has a smartphone and the ability to take decent photos from a smartphone itself without tweaking settings like focal length, aperture, ISO, shutter speed etc. is a huge deal for many people.

Do You Really Need Them?

Smartphone Photography

It depends. If you don’t have a DSLR and you want to explore photography in general then multiple cameras can be good for you because it will allow you to explore different angles and perspectives. Or, if you are a kind of person who just want to take decent photos and selfies, then a decent single or at the most a dual camera system would be more than sufficient for you. As far as image quality is concerned, it depends on the camera sensor and the software of the smartphone manufacturer. More megapixels don’t mean better image quality.

A 12 Megapixel DSLR can produce better image quality than a 20 Megapixel smartphone camera because of the size of the camera sensor. The larger the surface area, the greater amount of light captured by the sensor.

Google, in their Pixel smartphone used some advanced computational photography techniques to deliver some of the best photographs which could be ever taken from a single 12 MP smartphone camera.

So, it’s not a hard and fast rule to have multiple cameras in a smartphone. The advancement of smartphone photography may depend on Moore’s Law. Wait, what’s Moore’s Law? Well, let’s keep that for another blog post.

That’s all for now. Signing off.

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['Cameras', 'Smartphones', 'Mobile Photography', 'Augmented Reality', 'Technology']