Last February, I already blogged about the fact that dual cameras . So, in fact, it happened (I'm not a leading analyst, if anything, it was simple and so obvious :)). In the end, mobile photography needs to be developed somewhere, simply increasing megapixels is inefficient. And since the physically small size of the phone camera sensors and the limitations on optics do not allow you to “turn around”, you have to look for alternative solutions.
Today, HTC, LG, Huawei, Xiaomi, ASUS, ZTE, Lenovo and, of course, Apple (of course, not only them) have flagships with dual cameras. Perhaps only Samsung for some reason ignored this trend. Possibly due to technical issues. Indeed, recently I “ran through” that the early prototype of the Galaxy S8 still had a double module.
It should be noted that the technology itself is not new. If you remember, in 2010-2011 there was a boom in home 3D. And this affected not only TVs, but also smartphones. Models HTC Evo 3D and LG Optimus 3D were equipped with dual camera modules for capturing three-dimensional video, and their screens displayed glasses-free 3D content. In the market, this trend is even in the part of TVs. And the phones did give out a “blank” image and no one liked it. Dual cameras in them were used only to create stereo photos and videos. But the benefits of technology are actually greater.
Why are two main cameras good?
First, the two cameras expand the "field of view". If there is only one module, then it is universal - suitable for both landscape photography and macro photography. But the second module can be installed with a wide viewing angle and shoot cool panoramas without “software” gluing.
Secondly, the dual module improves the clarity and contrast of photos. Each camera can shoot a little differently, focusing on different details. The two frames are then combined to create the perfect picture.
Third, optical zoom. If desired, it can be installed for one camera module, but this will increase the dimensions of the smartphone, which is not in the hands of the manufacturer. When there are two lenses, one can be wide-angle (captures more in the frame), and the second - long-focus (“sees” farther). In this way, a 2-3x zoom can be obtained without degrading the image quality.
Well, the fourth - beautiful bokeh (background blur). In principle, smartphones with a single module can do something similar, but dual cameras have a much cooler effect. This is because the first camera focuses on the selected object, while the second effectively blurs the background. The pictures are then stitched together.
That's all the main advantages of dual modules. However, each manufacturer implements the technology differently, so let's dive into the specifics.
Apple Approach
As you know, only the older iPhone - 7 plus is "gifted" with a dual camera. First of all, with this step, Apple solved an important problem in the mobile world - the difficulty of using a full-fledged optical zoom. As already described above, the second camera has a telephoto lens and, compared to the first, provides zoom without digital zoom. Everything works very well, thanks to the software.
Due to the fact that the two cameras have different focal lengths, the option of shooting portraits also won. Again, I already wrote about this “feature” above - images from two cameras are connected, as a result, the object being shot is as clear as possible, and the background is artistically blurred. Maybe sometimes the effect seems too “artificial”, but still, two cameras implement it much better than purely software solutions.
Apple has imitators too. The new model ASUS Zenfone 3 Zoom (it was introduced earlier this year) also has a dual camera. And unlike its predecessor, the ZenFone Zoom (it used a multi-lens system) gives 2x zoom purely due to the different focal lengths. The model also supports shooting portraits in “bokeh”, and also stands out with super-fast phase autofocus.
LG
Long before the seventh iPhone saw the light of day, the modular flagship LG G5 was introduced with a dual camera. True, few people will remember this fact at all, since the phone was almost not seen on the market. They tried to make the G6 completely different, but it still has two main cameras.
Curiously, LG uses "two-chamber" differently than other manufacturers. The second lens here is not long-focus, but rather wide-angle - with a viewing angle as much as 125 degrees. There is no analogue of optical zoom, but you can shoot gorgeous panoramas - there is a LOT of room in the frame! True, the edges can be “blurred”, but this is not critical for everyone.
Huawei
This brand was one of the first to "resurrect" a dual camera in a smartphone. The Honor 6 Plus went on sale in early 2015. Since then, Huawei flagships have always come out with dual modules. Including the popular P9 and the latest P10. And here there is a very interesting feature: one camera shoots an exclusively monochrome image. This means it captures more light, delivers better sharpness, and is perfect for low-light situations. As a result, the image from two cameras is combined into a high-quality picture.
"Side" plus - you can shoot black-and-white photos in excellent quality (that is, better than programmatically "discolored" regular ones).
However, not only Huawei uses this technology. Last fall, hardware giant Qualcomm announced the Clear Sight platform, another incarnation of the same idea with monochrome photos. The cameras are supplied in a ready-made “chip”, which can be used without difficulty by any smartphone manufacturer. In particular, Xiaomi Mi 5s Plus boasts Clear Sight technology.
The Past, Present and Future of Dual Cameras
As mentioned in the introduction, the current dual camera boom is not the first of its kind. Once upon a time, Koreans were pioneers in terms of technology - back in 2007, the Samsung SCH-B710 model was introduced for the domestic market. It was equipped with two cameras (1 MP each), and the display could reproduce a stereo image. Apparently, the phone did not become popular, since there was no continuation.
In 2011, "tridesh" LG Optimus 3D Max and HTC Evo 3D were sold. Niche models almost did not attract the attention of buyers. And since the two main cameras were used exclusively for shooting 3D that did not become popular, they did not develop the idea.
In 2014, HTC, in a vain attempt to regain interest in its products, again remembered the dual camera technology. The flagship HTC One M8 was equipped with the main and auxiliary cameras (4 MP UltraPixel + 2 MP). The second was only good for blurring the background. And then it was done optionally - after shooting in the gallery.
The same technology was then used by ZTE in the Axon series and the Grand X Max 2 phablet, Xiaomi in the Redmi Pro. Plus a few more Chinese manufacturers. It is relevant even today. Huawei has a similar implementation of "two-camera" in the budget model Honor 6X. One module is a full-fledged 12-megapixel, the second is an auxiliary 2-megapixel module (only useful for "bokeh", but still an interesting "feature" to stand out from competitors).
Sometimes two cameras are installed on the front of the smartphone. The zoom function is relevant here - you can take regular and group selfies without difficulty. This implementation is found in LG V10/V20, Vivo X9.
The current flagships have already been mentioned above - iPhone 7+, LG G6, Huawei P9 / P10.
What's in store for dual cameras in the future? An interesting technology was introduced by Oppo earlier this year. It is called 5X Precision Optical Zoom - as you can easily understand, we are talking about 5x optical zoom. Two photo sensors are also used here, but there are no two lenses on the smartphone body. One of the sensors is hidden inside the case, a movable lens system is used, located at an angle of 90 degrees. Thanks to this, it is possible to keep the extremely thin body of the smartphone. In general, the design resembles a periscope (light enters the sensor through a special prism and a glass window).
Of course, at this magnification, any hand shake will blur the frame. Therefore, OPPO has also developed an advanced optical stabilization system for both the photosensor and the prism: correction is carried out in 0.0025-degree increments. OPPO superzoom-enabled smartphones have not yet been released, we are waiting.
Another technology that uses multiple cameras in smartphones was developed in the bowels of the Google Tango project. This is augmented reality. True, more cameras are required - three or more. And all of them are used to collect information about what is happening around and simulate virtual reality. By the way, smartphones based on the Tango platform already exist, for example, Asus ZenFone AR. I think the idea may well "take off", it's not for nothing that Google is doing it.
In any case, the use of multiple main cameras in smartphones is an interesting and promising topic. Do you also think? Would you like a smartphone with a dual camera? Or is it all a prank?
March 06, 2018The dual camera first appeared in smartphones at the end of 2014. And immediately she caused a double attitude towards herself. Some considered it an innovative achievement that opens up new horizons in shooting with a phone. And others reacted to the double camera with irony - they say that such smartphones are no better than single-camera ones. And manufacturers no longer know what to offer the user in order to stand out in pursuit of the attention of the public: either they reduced the size of devices, then increased the screen size, and now they are experimenting with the camera. Moreover, there were already attempts to use two cameras on one phone in 2007.
So, let's try to figure out what a dual camera in a smartphone means, and if necessary, then why? Do the two main cameras have advantages or is it just a fad. Let's figure out why a smartphone needs a dual camera, because, one way or another, but this is already a trend. And we will most likely see it more than once in the new products of 2018.
Stereo shooting: the first pancake is lumpy
Some phones equipped with a dual rear camera were designed to create so-called stereo photos. They can be viewed on a 3D monitor. Such pictures are obtained due to the presence of a small distance between the two cameras. Using special glasses, you can see that the photograph acquires volume. Among the phones offering dual cameras for such shots were the Samsung B710, LG Optimus 3D Max and HTC Evo 3D. These were the novelties of 2007, and the resolution of each module was up to 1.3 MP.
Model 2007. A Samsung SCH-B710 3D dual camera phone that had the ability to take 3D photos. It was equipped with two 1.3-megapixel sensors and a 2.2-inch display with a resolution of 240x320 pixels.
But, despite the uniqueness, users did not appreciate the option, and phones with the ability to shoot stereo with a dual camera did not gain popularity. But there are other reasons why smartphones are equipped with dual cameras. And users liked them much more.
Panoramic shooting and widening the field of view of the lens
Users have appreciated this option of a dual camera. Its essence is that one camera works with an angle of view of a maximum of 90 degrees. These are excellent indicators for shooting landscapes and other photos. But this was not enough for shooting architecture, as well as spectacular shots of relatively small objects such as cars, and then manufacturers began to equip phones with a second camera - especially for panoramic shooting, with a viewing angle of 120 degrees or more. The option is very fond of users, because a panoramic picture can be taken with one touch of your fingers. The second wide-angle camera is installed in smartphones LG V30+ (angle 120°) and LG G6 (with a view of 125 degrees).
Shooting with the second wide-angle camera of the LG V30+ smartphone with a 120-degree field of view Shooting distant objects
In most phones, if you need to capture a subject that is located at a distance, you will have to increase it with digital zoom, which will definitely affect the quality of the picture - sharpness and detail. Therefore, some manufacturers decided to add another additional camera to the main camera - with a telescopic function. The better the optical zoom is implemented in the second camera, the less digital zoom will have to be used. By switching between models, you can achieve excellent multiple optical zoom, without loss of quality.
An example of such a solution is the dual module used for optical zoom in . Both matrices in the phone are the same (12 megapixels), but one has fast optics with standard parameters, and the second has a limited viewing angle with a 2x optical zoom.
Enhance night, evening and indoor photos
In some smartphones, one dual camera module takes color photos, and one - black and white. The monochrome sensor receives a lot of light and is focused on the contours, as it only transmits shades of gray. And the color matrix is responsible for the brightness and realism of color reproduction in the photo. This results in high-quality shots where both colored objects appear bright and dark objects do not appear black. The advantages of a phone with such a dual camera are obvious - clear, detailed and high-contrast photos.
The first company to use dual cameras to improve detail and dynamic range of shooting was Huawei (for example, Huawei Honor 8, Honor 9). The same dual camera with a monochrome sensor is installed in the budget LeEco Cool1.
At dusk, the advantages of the dual matrix of Huawei Honor 8 are obvious. The monochrome sensor has more light sensitivity, so it captures more details 
Shooting indoors with the dual camera of the Huawei Honor 8 smartphone is another advantage of having a monochrome sensor. Data from both sensors are combined to achieve lifelike footage with excellent dynamic range and sharp focus.
Bokeh effect: two cameras required
Bokeh is a photograph in which the main subject is extremely sharp and the background is slightly blurred. This effect allows you to focus on the main image, and remove unnecessary distracting details. However, this emphasis cannot be achieved with a single smartphone camera, so some companies have taken the next step: one camera photographs the subject as clearly as possible using focus, and the second photographs the background, which is blurred by software.
To date, the best representative of the device with a dual camera for bokeh effect is the iPhone 7 Plus.
Both shots were taken with an iPhone 7 Plus. Left - normal shooting mode, right - shows how the bokeh effect works Dual selfie camera
Smartphones with a dual front camera are very rare on the market, but they may soon become popular. Today, they can be counted on the fingers, and Vivo X9 in terms of the totality of characteristics is the best of them. It will please selfie lovers, as it is equipped with two front modules of 20 MP and 8 MP, while it can simulate the bokeh effect no worse than the iPhone 7 Plus - but for selfies. Portrait photography has never been better. At the same time, the main camera with a resolution of 16 MP is also good.
4 cameras on a smartphone
Some manufacturers have gone even further and offered 4 cameras in a smartphone instead of two. One of these devices was (another name for this phone is Huawei Mate 10 Lite). In it, to the main and front modules of 16 and 13 megapixels, a 2 megapixel sensor was added to implement background blur. Therefore, a photo with a bokeh effect is taken not only by the main camera, but also by the front camera. There is a proprietary mode for artistic shooting at night with a tripod, as well as a background blur mode for shooting any subject, not just portraits and “live photos”, when a small segment of video is recorded along with a photo. However, the interesting bokeh effect on both cameras is the only difference between four cameras and two. In all other respects, Huawei Nova 2i is a standard device that requires normal lighting and a short distance to create beautiful photos.
As well as…
Why else do you need a dual camera on a smartphone? Let's list the options:
- To take a photo with interchangeable focus
- To make a seamless wide-angle panorama
- To make the camera get more light
- To determine the distance to photographed objects
- To unlock the phone by the contour of the face
- To take quick photos and refocus later
In any case, the era of phones with two main (or two front) cameras is just beginning, and we can assume that manufacturers will surprise us more than once with new features of dual modules in their developments of 2018-2020. Moreover, many have already figured out how to use a dual camera, and want to purchase such a camera phone as a replacement for their cameras-soap boxes.
This year, the trend of increasing the number of cameras in smartphones is especially clearly visible. In addition to the branded Google Pixel, there are no significant brands left, in the assortment of which there are models with only a “regular” single camera.
And if earlier only top-end smart phones received dual cameras, today they are already found with might and main in devices of medium and even entry-levels.
This year is also notable for the appearance of the Huawei P20 Pro smartphone, where not two, but three cameras have already been installed on the rear panel!
We will return to the three-camera Huawei, but for now let's talk about common dual camera modules.
What gives a dual camera?
Due to the natural parallax of two cameras placed at some distance, it is possible to better realize the effect of digital background blur. In many modern smartphones, this mode is associated with shooting portraits.
The subject remains sharp while the background is further blurred.
Blurring an Object (Samsung Galaxy S9+)
regular shot 
Applying a Blur Effect
The resulting image begins to resemble frames from serious system cameras, where such blurring, which is also called bokeh, is achieved naturally due to the peculiarities of the matrix-lens bond.
Before the advent of dual cameras, this effect was also among the features in some smartphones, but, as mentioned above, with dual cameras, blurring can be improved, although it certainly still turns out to be not perfect.
An additional (second) camera can also have a different viewing angle.
If its field of view is wider than that of the main camera, then a wider shooting area will enter the frame. This implementation option is not so common in smartphones. An example is LG smartphones (G5, G6, LG G7 ThinQ, V20, V30).
In LG G5, the additional camera has a wider viewing angle
The choice between the main and secondary camera with a wide field of view in the smartphone LG G5 se
A more common option is when the secondary camera has a narrower field of view. As a result, the zoom function is implemented. Typically, the equivalent focal length of the secondary camera is twice the equivalent focal length of the main camera, resulting in a 2X zoom.
This is found in smartphones Apple iPhone, Samsung, HTC and many others.
Samsung Galaxy S9+ secondary camera has a higher equivalent focal length and narrower field of view
2X zoom main and secondary camera shooting (Samsung Galaxy Note8)
Main camera 
Additional camera
But there are still situations when both cameras have the same viewing angle.. This is implemented in top-end smartphones Huawei, Honor. A proprietary solution is used here, where the sensor of the additional camera is not color, but black and white (there are no color filters on the pixels).
According to the manufacturer, the data received from the two sensors are combined in the final image, which gives a gain in quality. In addition, it becomes possible to create "natural" black and white images due to the matrix without color filters.
By the way, in its first and so far the only smartphone with a dual camera Sony Xperia XZ2 Premium, the manufacturer used a similar Huawei solution with the same viewing angles and the use of an additional black and white camera.
Come on more! The emergence of a smartphone with three cameras
Huawei marked this year with a very curious, in terms of shooting, smartphone P20 Pro. Its unique feature is the presence of three cameras on the back!
The bottom line is that in addition to the traditional Huawei bunch of two cameras with the same viewing angles (main and secondary black and white), they added another camera with a narrower viewing angle. It is noteworthy that in this case, the equivalent focal length is not two, as usual, but three times higher. It turns out that the zoom is already three times (3X).
Underwater rocks
As a rule, additional cameras are not nearly as good as the main ones. This is due to both technical features and financial ones.
They, as a rule, are simpler, have a smaller sensor size, lower aperture ratio, are significantly inferior to the main ones in autofocus, sensitivity, often lack an optical stabilization system, do not support a number of functions, etc.
It is not surprising that in difficult conditions (at night or with a lack of lighting), even if an additional camera is selected, shooting can still be carried out by the main one (this is provided by the developers).
The difference between the cameras can be even more noticeable in the middle and initial classes of smartphones, where absolutely frank rubbish is installed as an additional one.
A bit of history
The first smartphones with a dual camera began to appear a very long time ago.
You can remember LG Optimus 3D, released in February 2011, then appeared in March 2011, and about a year later it was announced.
But the purpose of the dual cameras of the above models was completely different. At the time, 3D (stereoscopic) video was in trend, and dual cameras were needed to capture stereoscopic photos and videos, which could then be viewed with a 3D effect on the dedicated screens of these smartphones.
The first attempt to use a dual camera to highlight an object in a frame with blur can be called (March 2014). But I must say that the quality of the blur in One (M8) was very poor.
In December 2014, the Honor 6 Plus featured a dual camera for background blurring and photo merging.
Samsung Galaxy Note8
Sony and HTC held out for a very long time (except for HTC One (M8)). Their two-chamber first-born, respectively, and the company released only in 2018.
Sony Xperia XZ2 Premium
How can smartphone manufacturers surprise modern users? Technologies do not stand still, giving birth to new opportunities and thereby shaping fresh trends. New a feature that is gaining popularity is the dual main camera at smartphones. Back in the summer of last year, devices with such an opportunity were single, but now many well-known and Chinese companies are releasing smartphones with two cameras. Let's take a look at the best of them.
Any normal user should ask, and Why does a smartphone need two cameras?, and is this not a publicity stunt of manufacturers? The thing is that companies are gradually coming to the conclusion that cameras in smartphones are already difficult to improve: neither increasing the size of the sensor, nor changing other parameters lead to significant progress in the quality of the resulting photos. The only way out is to increase the size of the camera, but then the phone will become much larger, so it is unlikely to find wide popularity among users.
The solution lay on the surface - equip the gadget with a second main camera. Since the technology is not yet mass-produced, manufacturers assign different functions to the additional module, but all solutions are aimed at improving photo quality. With the help of a dual camera, you can take pictures with different exposure settings and, by overlaying them, get a high-quality photo. Second chamber can be used for full optical zoom, and not digital, which is used in the vast majority of smartphones. With the optional camera, you can change the focus on finished shots, create blurred background. In some models, the second camera creates a black and white image, which makes the shooting process fast and the photo quality excellent.
And now let's see what the modern market offers us and take a look at the best dual camera smartphones of 2017.
The smartphone is equipped 20 megapixel color camera and 12 megapixel black and white camera fromLeica. The principle of their operation is as follows: the monochrome module takes a picture, while capturing as much light as possible, and thanks to the work of the color module, the resulting picture is then painted, allowing you to get a high-quality picture. The camera works clearly, autofocus works quickly, the picture is very high quality, there are ample opportunities for manual adjustment of shooting parameters. The front camera has a resolution of 8 megapixels. 
Other characteristics of the novelty also delight. The gadget received a metal case and curved display with a diagonal of 5.5 inches and a resolution of 2560 * 1440 made by technology AMOLED. Responsible for performance 8-core processor, whose cores operate at a frequency 2.4 and 1.8 GHz. Stock RAM 4 and 6 GB in different versions, the main one is 64 and 128 GB, respectively. The gadget received a fingerprint scanner, an infrared port, 4000 mAh battery and fast charging function. Delight, not apparatus! The price starts from $760.
LG V20
Oukitel U20 Plus
it cheapest dual camera smartphone but at the same time it is high quality and functional. It costs only $88 and proves to users around the world that a dual camera and the ability to take high-quality photos is not only an opportunity for flagships. For a ridiculous price, you can get not just a productive device, but also quite nice. In its design, you can see something in common with the latest iPhones, and metal case together with 2.5D- glass makes a lasting impression.
Most Affordable Dual Camera Smartphone got a 13 megapixel module fromSonywith interpolation up to 16 MP and an additional VGA camera. Photos get excellent detail, and it also becomes possible to take pictures with a blurry background. The front camera received a resolution of 5 megapixels, resolution screenFull HDand a diagonal of 5.5 inches is distinguished by the presence of a protective glass. Uses a 1.5GHz quad-core processor, 2 GB RAM and 16 GB main memory. There is a fingerprint scanner, two SIM card slots, support for 4G, battery capacity 3300 mAh. This smartphone is worth taking even for those who do not put a prerequisite for the presence of a dual camera - the model is good in all respects and perfectly balanced in terms of price and quality.
