Dual cameras explained: how do they work and what are the differences?

As this year’s Mobile World Congress in Barcelona clearly proved, a new trend has officially started in the smartphone world, and it’s that of the dual camera. Granted, the idea itself isn’t exactly new: in fact, it goes back at least to 2011 when the HTC Evo 3D, the first notable phone capable of recording 3D video, was released. While this particular application of the idea never really panned out, manufacturers are still keen on further exploring alternatives, judging by many of this year's upcoming flagships.

Even if the general idea of using two sensors to take one photo is shared between these devices, this is as far as similarities go, as each phone maker has a slightly different opinion regarding the way this tech should work. This, unfortunately, can be a major source of confusion, but luckily for you, we’ve taken on the task of demystifying the hot new thing in tech, so you don’t have to. So whether you’re in the market for a new device, or are simply wondering what all the fuss is about, we’ve got you covered:

The Apple approach

Let’s start with the most obvious contender first: the iPhone 7 Plus. Launched last year, Apple’s larger flagship offered a feature its sibling lacked: the dual-camera setup on its back. With it, the company chose to address a small yet important problem in smartphones: the lack of optical zoom. Sure, there’s always the option of zooming in digitally, but it’s a lossy and bad-looking one.

The iPhone 7 Plus’ camera solves this in a rather inelegant, but still ingenious way: the second camera on its back uses a different, permanently zoomed in telephoto lens, with the device switching between them whenever necessary. While this sounds like a hacky solution, it works wonders, in large part thanks to Apple’s software, which makes the transitions as unobtrusive as possible.

A side effect of this approach is that the two rear cameras also have different focal lengths, which Apple utilizes in a good way: Portrait Mode. Even though it was added in an update some time after the phone’s release, it’s still become one the device's defining features. In short, it works like this: the image from the two cameras is combined into one, with the person or object in the foreground being the only thing in focus. While the effect can look a bit artificial at times, it’s still light years ahead of the purely software-based solutions we’ve had before that.

While the iPhone 7 Plus is the most well-known device using this approach, it’s not the only one. At this year’s CES, Asus showed off its upcoming Zenfone 3 Zoom, which does pretty much the same thing, but with a triple zoom and improved focusing capabilities. It also includes its own portrait mode functionality, though it remains to be seen how well it actually performs in real-life conditions.

The LG approach

Before Apple had the iPhone 7 Plus, however, LG had been doing something similar with its LG G5, though few people are aware of that fact, what with phone being a rather spectacular market failure. The upcoming G6, however, hasn't abandoned the idea, and has in fact improved upon it with an upgraded second sensor.

Compared to Apple’s approach, the way LG handles the second camera is almost opposite: where the 7 Plus has a permanently zoomed-in camera, the G6’s appears zoomed out, due to its much wider field of view. This method isn’t really widely used, though the G6 could soon change that, as we expect it to sell pretty well. Some people, however, might not be pleased with the results, as the wide field of view also noticeably distorts the image, particularly along the edges.

The Huawei approach

This idea, as implemented by several of Huawei’s flagships, including the upcoming P10, is the most technically complicated of the bunch – it, again, involves two separate sensors, but the difference here is that one of them shoots exclusively in monochrome. This, in practice, means that the camera setup is more sensitive to light, and can therefore take better photos in low-light conditions.

A bonus of this approach is that users can take monochrome pictures of much higher quality than color ones, which is a welcome addition for those who like the effect. Unfortunately, in our review of the Huawei P9, which uses almost the same tech as the P10, we found video quality to be quite lacking, though photos were still of adequate quality.

Even if Huawei is the company spearheading this particular approach, it’s far from the only one to use it. Just last September, Qualcomm unveiled its so-called Clear Sight technology, which is another implementation of the same idea, but more easily and cheaply accessible to manufacturers. Xiaomi has already used it in last year’s Mi 5s Plus, and other device makers are bound to jump on it, too, so we'll likely be seeing more of it in the future.

Past, present and future

While these are the popular ideas being used right now, they are certainly not the only ones available. For example, the aforementioned HTC Evo 3D was designed to use its dual-camera module for stereoscopic 3D, and even featured a glasses-free 3D display (the same idea as in the Nintendo 3DS). Unfortunately, 3D turned out to not be as popular among consumers, prompting the eventual abandonment of the idea.

A much less popular approach that is still used nowadays also warrants mentioning: the one used in the mid-range honor 6X, as well as some of HTC's older flagships. It relies on two very different sensors, one with high and one with low resolution, and uses the second one only for various special effects, including iPhone-like bokeh. Most of the time they're a fun but cheap way of making an image more interesting, though for many users this is all that's needed.

As for the future, Oppo just recently showed off its newest camera tech, dubbed 5x, which, too, features a dual-sensor setup, but with a slight twist. With it, one of the sensors, which is attached to a telephoto lens and hidden inside the device’s chassis, users can have up to 5x “lossless” optical zoom, which could prove to be far better than current tech. We haven’t seen this idea implemented in a real product just yet, but we expect Oppo won’t keep us waiting for too long.

Another possible use of the technology is represented by Google’s Tango platform, namely augmented reality. Granted, we’re cheating a little here, as Tango requires three or more sensors to function properly, but the idea is generally the same: using a multi-camera module for a singular purpose. And the results themselves are promising, even if the platform doesn’t yet feel like a finished product.

So far there’s only a couple of devices supporting Tango out in the wild, but it may turn out to be a Big Thing some time in the near future, provided Google polishes it well enough. And so do multi-camera systems, in fact – while current solutions have their own problems, those are diminishing with each subsequent release, and we’re excited to see what’s to come next.



3. Plasticsh1t

Posts: 3109; Member since: Sep 01, 2014

"the one used in the mid-range honor 6X, as well as some of HTC's older flagships. It relies on two very different sensors, one with high and one with low resolution, and uses the second one only for various special effects, including iPhone-like bokeh". "HTC older flagships" "iPhone-like bokeh" https://imgur.com/gallery/c4jPKEF I wanna rage!

4. Odeira

Posts: 300; Member since: Jun 29, 2012

HTC's execution was,.. well,.. S**T. Who cares if you were the first to do it, the world only cares about who did it BEST. And to date, the iPhone 7 does it better than anyone else out there (I'm referring to the DoF / Portrait mode. Actual photo quality was not considered, that's for another debate.)

7. Mixkhata1

Posts: 162; Member since: Feb 26, 2017

It's true. Similarly, Samsung tried to implement fingerprint scanner right after iphone 5s used it so they botched it and Galaxy S5's fingerprint scanner is as good as sh*t. It doesn't really matter who gets it first. What matters is the end result. If an item or function is half-baked, it's probably a good idea to NOT include it and make consumers furious.

10. sachouba

Posts: 267; Member since: Jun 08, 2014

Since my S7 Edge, which only has 1 camera, is able to take photos in its "Portrait" mode with about the same quality of bokeh as the iPhone 7 Plus (just like the S6 and the S5), I don't know how a dual camera with such small improvement over a single camera can be considered a success. Huawei, on the other hand, does it much better than Apple, when it comes to depth of field.

29. darkkjedii

Posts: 31614; Member since: Feb 05, 2011

When you constantly seek to shoot Apple down, no matter what they do, or how good they do it, people look at you as a blind fanboy, who won't see things from any other perspective than that.

11. maherk

Posts: 7017; Member since: Feb 10, 2012

Portrait mode can be brought to the iPhone 7 as well, but Apple wants people to pay more for a software feature that they had to convince everyone that this feature relies on the dual camera setup. The best dual camera setup is that of LG's, and they perfected it with the G6.

22. bucky

Posts: 3795; Member since: Sep 30, 2009

The reviews of the g6 camera across many websites state otherwise.

25. maherk

Posts: 7017; Member since: Feb 10, 2012

All the reviews I came across throw nothing but compliments at the G6's camera.

27. trojan_horse

Posts: 5868; Member since: May 06, 2016

And the G6 they're reviewing certainly isn't a final consumer-ready one, but a pre-production unit.

46. Remmy

Posts: 189; Member since: Jul 31, 2012

Knowing how fast iPhones capture and process photos, even the single camera on the iPhone 7 can replicate the same faux-bokeh effect. Sony's background defocus is slow and you have to be super steady to achieve good results.

5. Cat97

Posts: 1979; Member since: Mar 02, 2017

When using dual cameras, 1+1 does not equal 2, but actually less than 1. Dual cameras is a gimmick which does not benefit consumers at all, it is detrimental to image quality and to an extent to battery life. They take up valuable space, and then the Bill Of Materials is more expensive for manufacturers, which need to make compromises for the main camera (a good example is LG G6 using two 2 years old camera modules with underwhelming performance for 2017). I would much rather prefer a good single camera to a mediocre dual camera. I hope this trend will be over very soon !

12. Settings

Posts: 2943; Member since: Jul 02, 2014

Lol whut?! Yet another hater whose judging tech he or she still haven't used. More like 1&1=1, those camera work in unison rather than 2 separate. And whats wrong with using 2 yr old camera sensor? It stil can take 2016/2017 sensors to the floor.

17. ShadowSnypa786

Posts: 624; Member since: Jan 06, 2017

I agree totally the S7 edge isnt a dual camera phone yet its photos are just as good as Huawei's, Apple's and LG's dual camera set up. Plus these phones all came out 6 months of after the S7 edge. The Pixel camera is rated as the best smartphone camera and guess what?? It isn't a dual camera set up either. If you want dual camera's to use bokeh effects or a wide angle go for it, but to say having a dual camera setup makes it better than a normal single camera is just rubbish.

28. trojan_horse

Posts: 5868; Member since: May 06, 2016

But the S7 edge's single camera does not match the FoV (field or view) of the G6's camera. So LG's dual-camera implemention is useful for tourists who want to take photos of beautiful landscapes or a zoo park.

9. sachouba

Posts: 267; Member since: Jun 08, 2014

"THE IPHONE 7 PLUS MADE THE DUAL CAMERA MAINSTREAM" LOL The democratization of dual cameras has nothing to do with all the HTCs, LGs, Huaweis that have been featuring a dual camera for years, of course. I guess Apple invented the technology, too, right?

13. darkkjedii

Posts: 31614; Member since: Feb 05, 2011

That's odd, that you don't actually see what the writer means by that statement. Of the 3 OEM's you named, do you think the mainstream consumer uses them for dual cameras as much as Apple? Who dual camera phones are in more hands? Making it mainstream isn't necessarily making it better, it's shining more light on it. And no Apple didn't invent the tech, you said that, not the writer. If you and I both make a product, and although yours is better, mine is in the hands of 5 million people and your is in the hands of 500...who's making it more mainstream? That's all he's saying, no need to read more into it.

18. maherk

Posts: 7017; Member since: Feb 10, 2012

Come on DJ, when the writer claims that Apple made it mainstream, and mention Apple 1st in this comparison when they were the last to adopt it, he is sending this message that other OEMs will start to adopt the dual camera setup now that Apple did. And I am 100% sure that the LG G5, Huawei's P9 and P9 Plus, Mate 9, HTC Evo 3d, HTC m8, M9 Plus, etc..., have more units sold combined than the iPhone 7 Plus, so this also means that there are more phones with dual cameras out there than the iPhone 7 Plus, which cancels the idea that the iPhone 7 Plus made it mainstream.

19. darkkjedii

Posts: 31614; Member since: Feb 05, 2011

No bro, that would actually reinforce the notion that they brought it to the mainstream. Apple is often late to the game, we know that, but When Apple and Samsung decide to do it, others jump on board.

31. mikehunta727 unregistered

I actually bet that all those devices combined don't outsell the 7 Plus sales in total. Over 40 million 7 pluses sold already, most of those devices barely reached a few million in sales

35. maherk

Posts: 7017; Member since: Feb 10, 2012

Where did you get your numbers from?

39. cmdacos

Posts: 4330; Member since: Nov 01, 2016

Thin air clearly.

45. mikehunta727 unregistered

Sorry mate but if you just look at global shipment numbrrs and specifically HTC sales in the past few years have been completly abysmal. Huawei' and Xiaomi and all these other companies sales are majority of their bottom line and not flagships which have these dual camera setups. The proof is right there literally in years of data, you just have to take a look at it The 7 Plus has sold a shit ton already and is easily the leader in just under a year in terms of "mainstream dual camera" vs all these OEM'S combined

44. mikehunta727 unregistered

Global shipment numbers of OEM's for the past years. The M8/M9 combined sold less then 10 million together, HTC barely sold 1 million HTC 10'S last year Evo 3D was a massive flop and was a Sprint exclusive only, The Plus model has outsold the smaller 4.7 inch iPhone by about 5:1 in the past few years. The 7 Plus has outsold all the devices mentioned already, 70 million iPhone's record in the past quarter

40. sachouba

Posts: 267; Member since: Jun 08, 2014

It depends on how you define mainstream. If "to make mainstream" means "to sell the most smartphones with dual cameras", then Apple probably made the tech mainstream. But it doesn't make any sense, because then, Apple will be the manufacturer that will make AMOLED displays and wireless charging mainstream, and has also made waterproofing, big screens, multi-windows and smartwatches mainstream. That's not what mainstream means to me. As far as I'm concerned, "to be mainstream" means that many people know about it and are interested in it, thus dual cameras were already mainstream before the iPhone 7 Plus, just as AMOLED screens and wireless charging.

14. ibend

Posts: 6747; Member since: Sep 30, 2014

it isn't even mainstream right now.. if any, huawei and LG is the one who start it..

15. darkkjedii

Posts: 31614; Member since: Feb 05, 2011

Again lol. Starting it, and bringing it to the mainstream are two different things. You guys have such a hard on for Apple, and won't to troll Apple so bad, you allowing your dumb side to blind you as to that simple meaning of mainstream. No, Apple didn't start it, but they've moved it further into the limelight than HTC, LG, or Huawei has. Limelight = mainstream consumer.

16. maple_mak

Posts: 953; Member since: Dec 18, 2013

No, is HTC first.

20. tedkord

Posts: 17471; Member since: Jun 17, 2009

The key word is mainstream. It is the best known example, and sold more than all the others. The odds are more people know the iPhone 7+ has a dual camera than all the others combined. I don't recognize the author of this article, so I don't know his body of work, but I didn't see anything really outrageous here. He didn't claim Apple invented it, or even that they did it best. The iPhone did make the concept mainstream. True, it was only due to an already large existing sales base. Most folks didn't buy their 7+ because of the dual camera. Heck, most would have bought it even if Apple had removed the camera and called it courage. That's all irrelevant to the point.

21. mikehunta727 unregistered

You hit it on the head. It's really this simple and the fact that most pro Android users on this site don't understand this is pretty pathetic lol

24. kiko007

Posts: 7521; Member since: Feb 17, 2016

Pathetic is too harsh a word. Many of them just get triggered whenever someone mentions the word iPhone in an article. It's mental conditioning you see....

* Some comments have been hidden, because they don't meet the discussions rules.

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