Understanding smartphone dual cameras

In case you missed it, Kenyan media personality Caroline Mutoko did an interesting “review” of the Samsung Galaxy Note 8 when it launched in Kenya. I have the word review in quotes because it is not the typical review you would get from tech heads like ourselves or our peers in the industry that is full of spec listings, benchmarks and petty nitpicking that you wouldn’t care about and whatnot. Rather, it’s a shameless promotion of Samsung’s latest premium smartphone disguised as… a review.

I take no issue with that approach since, to each their own, but watch from the 3.45 to 4.05 mark and, like Ms Mutoko famously says in her videos, come back for more:

Here’s the thing, that declaration that the Galaxy Note 8 having two 12-megapixel cameras means that the two collaborate to produce one big 24-megapixel snap is neither here nor there. It’s wrong. Much as it is easier to go all out and make fun of that wrong assertion, I am of the opinion that it’s really not her fault. Many of us just don’t know how dual cameras and other technology on our devices work and we’ve become fodder for the incessant marketing from mobile tech companies hoping to push their latest technology our way and appealing to our naive souls.

Could she have done better? Yes. But what’s done is done. Water under the bridge now. Here’s how dual-cameras work on various popular devices:

The Huawei way

Chinese device-maker Huawei latched onto the dual-camera craze just before Apple blessed the trend and made it mainstream with the iPhone 7 Plus last year. The Huawei P9, Huawei’s flagship smartphone for 2016 which came months before the iPhone 7 Plus, had two 12-megapixel cameras at the back. Thanks to its partnership with German camera optics powerhouse Leica, the focus on the cameras on the P9 was strong. One of the two 12-megapixel lenses captured images in black and white akin to the popular monochrome Leica camera while the other took the usual standard coloured (RGB) photographs. The two snaps, which are taken at the same time, are then combined to produce a single sharp image with high contrast and more detail.

I used the P9 extensively last year and I loved this particular working mechanism. I would later spend an entire year seeing similar results on the P9’s big brother, the Huawei Mate 9, whose 20 and 12-megapixel dual-camera setup works pretty much the same way. The 20-megapixel camera takes the black and white photos while the 12-megapixel one takes the coloured snaps. Like in the P9, all images are captured this way even though users have an option to single out the monochrome lens and just take black and white images with it. Whichever the case, results are still amazing. The more details captured thanks to the 20-megapixel black and white lens come in handy when one wants to apply depth and bokeh effects if the wide aperture mode is enabled.

Huawei has lent this tech to its subsidiary, budget smartphone brand Honor, which showcased it for the first time on its popular Honor 8 smartphone last year albeit without the Leica branding next to the two lenses.

The Huawei way with a twist

This Huawei way of doing things is something that another Chinese smartphone maker, Beijing-based Xiaomi, has aped. To some extent. Xiaomi’s update to its flagship Mi5 last year, the Mi5s Plus, featured two 13-megapixel cameras at the back. One was for capturing images in black and white while the other would capture them in colour. However, unlike Huawei which lets its devices shoot images using both lenses at the same time and combining the effects on the fly unless a user opts to shoot in black and white, Xiaomi does things a bit differently. For images to be captured using both monochrome and colour image sensors, one has to turn on what is called a Stereo Mode, otherwise, just colour snaps will be taken. There’s also an option to take black and white snaps but that is prohibited if one turns on manual (pro) mode, something that is not the case with the Huaweis.

READ:  3 ways to get all your favourite apps on the new Huawei Y7p

The HTC way

HTC had a smartphone with a dual camera when the concern of many an Android smartphone enthusiast was still plastic designs on flagship smartphones.

HTC’s best days in the smartphone market may seemingly be behind it but before its eventual fall from grace, it used to try. After failing to convince the world that its impressive and well-designed One M7 was worth throwing some $$$ on, HTC did a take two. It refreshed the M7 the following year (2014) but added an interesting feature next to the infamous ultrapixel camera: another camera. The second camera on the back of the HTC One (M8) was 2-megapixels while the main camera was 4-megapixels. The former would capture all the depth information so that final product of images captured with the main camera would be detailed and allow users to add effects like bokeh and what have you. This is an arrangement that lives on to date with its implementation showing up in devices made by companies like Xiaomi (they try everything under the sun these ones, from Huawei’s way to Apple’s telephoto system – more on that in a bit – to this tried and tested HTC way).

Xiaomi’s very first dual cameras on a smartphone worked this way. The Xiaomi Redmi Pro had a pair of 13 and 5-megapixel cameras at the back. The 13-megapixel camera was the main shooter while the 5-megapixel sensor captured depth-of-field data that would allow users to create the desired blurred/bokeh effect on snaps they had already taken.

It’s not just Xiaomi that has done this. Even a subsidiary of the guys who are famous for doing the black and white + colour dual camera arrangement, Honor, has done so with devices like those in the Honor 6 family (6X, 6Plus).

Another Chinese device brand that has made inroads in Kenya and Africa at large, Tecno, last year deployed a similar working mechanism for the dual cameras on its flagship device, the Phantom 6.

The LG way

LG has had an interesting take of this whole dual camera thing. It did it for the first time last year with the G5 and it did it again this year with the G6.

The G5 has a pair of 16 and 8-megapixel cameras at the back. The former is for taking normal snaps while the latter takes advantage of its wide field of view (up to 135 degrees, much more than the human eye’s field of view) to take wide-angle shots. The LG V20, LG’s flagship smartphone for the second half of 2016, had a similar dual-camera setup. This is the same arrangement that LG has kept this year in the G5’s successor, the G6. However, in the case of the G6, LG opts for a pair of 13-megapixel cameras at the back (with the wide-angle one being able to capture a 125-degree field of view) before changing its mind and going for a pair of 16 and 13-megapixel cameras in its V30 and V30+ smartphones months later.

The 3D way

“The three-way” would’ve made a much better sub-heading… no? Okay.

LG has been making smartphones for a while. Before the era of the G series arrived, it used to make outliers like the Optimus 3D, which at some point even went on sale in Kenya. Like the name suggests, the LG Optimus 3D was supposed to usher the mobile world into the 3D era, something that never came to pass. To tout its 3D credentials, it turned to a pair of cameras on its back so that users could be able to create 3D content (photos and videos) and so there we were with dual cameras on a device running Android 2.2 (Froyo) in 2011. Dual cameras on a phone are not a new thing.

Of course, LG wouldn’t have been let to have its shine. The Samsung of those days, HTC, chimed in with its own 3D phone, the HTC Evo 3D, a device that was exclusive to the hippy American market. There were so many Evos at that time. Remember the Evo 4G? I digress…

The Evo 3D’s cyborg-like dual-camera arrangement encompassed two 5-megapixel cameras. One was for taking normal 2D shots while another was for amplifying everything to the buzz tech of that time, 3D.

READ:  New Xiaomi Mi Store opens on Aug. 10 in Nairobi’s CBD with sales of the Mi Band 4, two Mi Home stores to open at Sarit Centre and Westgate soon

The Nokia way

Yes, definitely, we cannot talk about cameras without talking about Nokia.

HMD Global does a fusion of some of the technologies we have seen so far in use on other devices for its flagship smartphone, the Nokia 8. The Nokia 8 has a pair of 13-megapixel camera sensors at the back that go a long way in contributing to its overall good looks. What’s even more interesting about them is the way they work. One camera, instead of two, handles the processing of both black and white and coloured images. One camera has two sensors: monochrome and colour. The other camera takes wide-angle shots.

The Apple way


In more ways than one, the arrival of the iPhone 7 Plus last year marked an important moment in mobile device history: the mere presence of a dual-camera setup on the iPhone 7 Plus meant that dual cameras would, henceforth, become a must-have feature on devices. True to form, dual-cameras are now everywhere and are not just a preserve of the premium segment.

The iPhone 7 Plus’ dual-camera setup differed slightly with what we had seen before. The duo of 12-megapixel shooters at the back had dedicated tasks. One would be the usual iPhone camera even though Apple prefers to call it a “wide-angle” camera while the other would be a “telephoto” lens. What telephoto means here is that the camera would allow users to zoom while taking photos up to two times without any loss in quality. As a user of the camera on your smartphone then you know that image quality is severely tampered with and degraded if you zoom (digital zoom) in while taking a photo. That was supposed to not be the case while using the iPhone.

Working together, the two cameras combine to add more details and depth of field information, thanks to the “telephoto” lens. [This is why telephoto is in quotes.]

The iPhone 8 Plus works the same way as the 7 Plus. As does the iPhone X.

It did not take long for the competition to ape the feature and one can now witness similar arrangements on the OnePlus 5 and Xiaomi smartphones (like the Mi A1 we’ve been lusting after).

The person who inspires my explainer pieces, like this one, Robert Triggs, has an interesting explainer article on the whole optical zoom thing. If you need to do some further reading, this is where you should start.

The (contentious) Samsung Galaxy Note 8 way

The elephant in the room as a result of Ms Mutoko’s gaffe is, then how do the dual cameras on the Galaxy Note 8 work? Short answer: like those on the iPhone (see above description). Long answer, read on.

What sets the Note 8 apart is that both cameras have optical image stabilization (OIS), a first on any smartphone (the iPhone X also has the feature).

One of the pair of 12-megapixel cameras on the Galaxy Note 8 allows users up to two times optical zoom (using the telephoto lens) while the other lets users take “wide-angle” shots. Quotes again because a 77-degree field of view doesn’t really qualify as that wide a field of view. At least not when compared to LG’s 120-135 degree magic.

The telephoto lens also captures more depth-of-field information that comes in handy when blurring the background, something that Samsung is calling Live Focus.

As a bonus, Samsung is giving users of the Note 8 another “feel good” feature: they can take snaps that incorporate the primary tasks of both dual cameras: zoomed in up to two times and wide-angle.


Yeah, it’s not as easy as 12+12 to understand this whole dual-cameras business. You might need to join a business community.

Have something that you believe I need to have a look at? Hit me up: echenze [at] androidkenya.com