Why does a smartphone need a dual camera on the back? The main advantages of a phone's dual camera over a regular one. How dual cameras work in smartphones

Plans to launch a device that will have two camera modules at once, all other manufacturers are alarmed, rushing to vying with each other to launch smartphones with two cameras. Some managed to do this quite conveniently and efficiently, some did it below an acceptable level, and some managed to bring such an idea to life in an extremely terrible way.

In fact, just this year at a congress in Barcelona, ​​a trend in the development of the smartphone universe was launched, but the idea itself is no longer new. For quite a long time, two modules have been used in devices (for example, the HTC Evo 3D, released back in 2011!), but it was in the coming year that manufacturers began mass production of this type of phone.

But what exactly are the advantages of a dual camera? How does it work, what amenities and functions does it provide to the average person, and what should you ultimately choose – a device with two or one module?

The principle on which a dual camera works

The principle of operation is no different from a single camera. The light passing through the lens lands directly on the matrix, and then the received information is read from this sensor by the processor, which subsequently transforms it into either a video or a photograph.

A dual camera works in exactly the same way, only there are not one, but two matrices. And they work completely autonomously from each other. Consequently, any gluing of signals and their processing is carried out by the processor. And the final quality of the photograph depends on its advancement.

The use of dual cameras in smartphones

There are quite a lot of use cases here.

Regarding optical zoom

One of the cameras built into the iPhone 7 Plus is aimed specifically at optical zoom. One of the modules has a wide-angle lens type, and the second of the lenses makes it possible to take photographs with zoom, the quality of which does not decrease.

When the zoom was only digital, in other words, the smartphone took pictures in 16 MP, cutting off the desired fragment with the processor, and the final photo was 8 MP, as a result, the quality also dropped. Now that one of the modules has optical zoom capability, it becomes possible to save high-quality photos.

Dynamic range

Not all smartphone manufacturers have started using a second module to achieve optical zoom. For example, the dual camera found on the Huawei P10 is designed to improve dynamic range. It lacks optical zoom capabilities. One of the modules in this model shoots only in monochrome. According to the developers themselves, this increases the level of shadow detail, and as a result, much better image quality.

Increased detail

Sometimes manufacturers insert different matrices into each module. One of them has a smaller megapixel value, but the aperture ratio in this case is higher. And the other has a lower aperture level, but the megapixel value is much higher. And after the two signals from each of the modules are combined, the picture is more detailed. The thing is that one of the images provides information about the color content of the composition, and the second - directly about the details of the image.

Change on focus

Some manufacturers use the second module to make it possible to take photographs in which it will be possible to change the focus after you have taken and saved the photo.

Blurred background

Well, of course, any smartphone that now has a dual camera is “trained” to create an effect called depth of field, that is, blurring objects in the background.

Essentially, in reality, it is a software process. The second camera in this case is necessary only to indicate as accurately as possible the position of the focused object in space. Pictures are taken on each of the cameras, both images are compared by the processor, and as a result, it is determined which of the objects you wish to see in the foreground. Then, in real time, a certain filter is applied to the image, due to which the background is blurred. Also, often, it is possible to independently specify the level of blur for the image. This concept is called a program aperture. And the more open it is, the greater the level of background blur will be. But in this case, more necessary and even probably important details will disappear from the image.

Software shooting algorithm

Software algorithms are extremely important in cases where a dual camera comes into play. They are necessary for image processing. If the process of the algorithms is error-free, then the depth of field effect will be quite accurate. Necessary and important objects will not be erased, and the edges of the foreground object will be clear, defined and smooth.

But today there is no camera of this kind that could, in any case, and with 100% accuracy, determine exactly where the border of the background begins and where the contours of the object end.

Dummies as dual cameras

In pursuit of profit, some models have appeared on the smartphone market that actually have a dual camera, but one of the modules is a dummy. Since it is difficult for an ordinary user to determine whether both cameras work and how exactly they work, unscrupulous manufacturers decided to play on this. Also, a similar line was followed by underground organizations that produce counterfeits of well-known smartphones at low prices.

In some models, one of the two cameras does not take pictures at all. The smartphone visually has two cameras, but only one works. In other models, both lenses are equal in characteristics, or shooting is carried out with both, but no software processing occurs.

Due to the fact that it is sometimes difficult for an amateur to distinguish a photograph taken with a regular camera from a photograph that was taken using a dual camera, this has allowed many unscrupulous manufacturers to profit well from this year’s trend.

Of course, among the best is the iPhone 7 Plus, which was presented to the public last year. Things are even better in this regard for the iPhone 8 Plus, which has just entered the market. This also includes the iPhone X, which will go on sale at the end of autumn.

The iPhone 7 Plus has two cameras, each with a resolution of 12 MP. One of the lenses is wide-angle, and the second is telescopic. A wide-angle lens allows you to get more information about the light in the image, and the second allows you to implement optical zoom.

Also quite a powerful model with two cameras is the new Huawei Mate 9 Pro. It has a built-in black and white camera with a resolution of 12 megapixels, and a color camera with a resolution of 20 megapixels. A camera that shoots in monochrome colors takes a picture, receiving a large amount of information about the light content of the image, and a color photograph makes it possible to color the picture, obtaining an image in high quality.

And finally, Samsung also distinguished itself by introducing a phablet. This is the first such experience of a Korean company, but the new product is already recognized as one of the best for photography. Galaxy Note 8 is equipped with a pair of 12-megapixel sensors, one of which has an f/1.7 aperture.

Price of smartphones with dual camera

All of the above are, without a doubt, excellent. But the question immediately arises: what will be the price for a smartphone with a dual module? After all, there are more elements, and the assembly process has accordingly become more complicated. In addition, the software also needs to be improved, otherwise the second of the modules will not be able to be used adequately and in the necessary way. And all this entails seemingly unnecessary expenses.

But in reality, there is no significant difference in price between devices with a single and devices with a dual camera.

Do you need a dual camera in a smartphone?

Having identified all the advantages and disadvantages of smartphones with a dual module, it is easy to conclude that, in general, a dual camera is more of an advantage than a disadvantage. In fact, if it does not radically affect the cost and only entails advantages, then there is nothing bad about it!

One of the most justified methods of using a second module is the possibility of improved optical zoom. It was commonplace that a smartphone has a constant viewing angle, and to take a close-up picture of an object it was necessary to get closer to it, otherwise the quality would drop sharply. Thanks to the telescopic lens, the situation has changed. One click is enough to bring a beautiful object closer, and a great photo is ready.

At first glance, it may seem that the dual camera is just another marketing ploy. But in reality this is not entirely true. In the article “Amateur photography: choosing equipment,” we already wrote that the main disadvantage of smartphones compared to compact digital cameras is the lack of optical magnification or “zoom.” A traditional smartphone camera has a wide-angle lens, which, firstly, is not at all suitable for photographing faces - they turn out to be too convex, with an unnatural geometry. Secondly, some distant objects turn out to be generally small.

The zoom lens in cameras is a rather complex design, but in short, the lenses in it move further and closer to each other. That’s why all the lenses in cameras are so convex, with the exception of certain models of compact cameras from Sony, where the lens is made flush with the body, a mirror is simply installed inside at 45 degrees, and the lenses move along the body.

In short, there is simply too little space for all this mechanics and optics in a smartphone. You can make the matrix (photosensor) and lenses small, but then the image quality will suffer. It would seem that the situation is stalemate.

But the solution turned out to be very simple - you just need to install not one camera, but two, with different focal lengths of lenses. Let one lens have an equivalent focal length, for example, 24 mm (wide angle), and the second - 50-55 mm (normal focal length). This way you can perform optical zoom by 2x by simply switching cameras in software.

Considering that these days the cost of the camera module itself in a smartphone (even a very high-quality one) is not that high, doubling the camera has practically no impact on the price of flagship smartphones.

However, optical zoom is not the only use of the second camera. Before 2x zoom became a trend, various manufacturers used the second camera for other purposes. In the LG G6, the additional module had, on the contrary, an even shorter focal length, thus turning into an ultra-wide-angle lens. And in the Huawei P9, the second camera took only black and white pictures, but with a higher light sensitivity. The smartphone software combined the images from both cameras, achieving less noise and greater sharpness than using only the first camera.

However, since the fashion for a second camera was essentially introduced by Apple in its iPhone 6 Plus, sooner or later all manufacturers came to exactly the solution that this company introduced, namely: 2x optical zoom. However, as we have already seen with the Huawei P9, information from both modules can be used to improve the quality of pictures.

Indeed, the dual camera expands the functionality of smartphone photography. For example, it allows software to separate the background from the subject (the subject is what the camera lens is focused on). The background can then be blurred to create the impression of a “professional” portrait or removed altogether - as if the portrait was taken in a professional studio.

Also, almost all smartphone manufacturers unanimously promise that in any case, when shooting, information from both cameras is used to filter out noise and achieve greater sharpness. This, however, may just turn out to be a purely marketing ploy. For example, if you compare the “single-chamber” iPhone 8 and the “dual-chamber” iPhone 8 Plus, it turns out that when shooting with a wide-angle camera, it is not possible to notice any difference. Unless the data from the wide-angle camera is used when shooting with the second camera - that would make sense. The fact is that, again, the laws of physics do not allow current technologies to implement the same aperture for wide-angle and “normal” smartphone cameras, so the main, wide-angle camera has a larger aperture and is capable of shooting with less noise in the dark than the additional one.

One of the main trends in the world of smartphones in 2017 was dual cameras. This is far from an innovation, since HTC decided to use two camera modules simultaneously in smartphones for the first time in the Evo 3D (2011) and later in the One M8 (2014). The Taiwanese implementation has not gained widespread popularity in the market. And so, in 2017, manufacturers decided to again rely on dual cameras.

This time everything worked out. After the release of the LG G5 in 2016, Apple decided to respond to its competitors - it became the company's first flagship with a dual camera. As a result, almost all well-known companies came to dual cameras - now they are used by Samsung, Apple, Huawei, LG, Nokia, Xiaomi, Meizu, Lenovo (Motorola), Essential, ZTE and even small Chinese vendors like UMIDIGI, Doogee, Vernee and others.

HTC Evo 3D with dual camera, 2011

Depth sensor

We'll start with the depth sensor, as this is the simplest form of dual camera system possible. In this case, the main camera is accompanied by a second sensor, the sole function of which is to create a three-dimensional map of the area of ​​the object being photographed. As you may know, a person sees the three-dimensional world in a two-dimensional projection, but is able to form a complete picture of the distance, shape, size and depth of surrounding objects. Our eyes are responsible for this, having stereoscopic ability due to different perspectives.

The depth sensor in the dual camera system works similarly to the main camera. Using the secondary module, the dual camera can tell you approximately how far away objects are in front of it relative to each other. This information is then used to separate the foreground object from the background.

An example of how the depth sensor works on HTC One (M8)

In theory and in practice, the depth sensor has its pitfalls. If the subject you are shooting does not have depth (for example, you may be shooting something flat), the camera will not be able to detect this and, along with the background, will blur the edges of the object. Even if the depth sensor does its job perfectly, the result does not look natural in any case. In DSLR cameras, the blur intensity increases with distance from the focus point. This is not the case with smartphones.

Dual camera systems with a special depth sensor are one of the rarest duos of photo modules. For the first time such a system was installed in the flagship HTC One (M8) - this is the most popular example. These days, the depth sensor is used in smartphones such as the Lenovo K8 Plus, that is, not in flagship models.

Monochrome camera

A slightly more popular implementation of a secondary photomodule is a monochrome camera. In such a system, the main camera is complemented by a similar sensor, the peculiarity of which is monochrome shooting. Both cameras usually have the same sensors, aperture ratios, lenses and focusing systems. The only difference between the two is that the second camera lacks an RGB color filter. This means that a monochrome sensor cannot capture color information, but it can capture more light than a regular camera.

A dual camera with a monochrome sensor takes two photos at the same time. The operating principle of such a system is to combine images from both cameras into one image. As a result, the two combined images have more detailed information and a reduced noise level. In addition, you can take only black and white photos with a monochrome camera and get the highest image quality. The color module cannot provide such a result even after applying the B&W effect.

B&W mode of monochrome camera on Huawei P9

Wide angle camera

For the first time, a dual camera with a wide-angle lens debuted in the LG G5 smartphone early last year. LG has installed a 16-megapixel primary sensor (29 mm) with f/1.8 aperture and an additional 8-megapixel sensor (12 mm) with f/2.4 aperture in its new flagship. The 12mm focal length gives the secondary camera a significantly wider field of view, which captures a much wider area of ​​the scene without the need to deliberately move away from the subject.

The wide-angle camera is mainly used in LG flagships. Motorola recently equipped its new Moto X4 smartphone with such a system. The wide-angle lens brings a unique perspective to mobile photography that no other smartphone camera can offer. In addition to its practical value (such as capturing a large group of people at close range), a wide-angle sensor also allows you to create beautiful landscapes by capturing the entirety or at least most of the scene.

Wide-angle and ultra-wide-angle modes on the LG G5

With good implementation, such a dual camera system can be very useful indeed when it comes to certain shooting scenarios. LG is going its own way, and that's good.

Telephoto camera

We come to the last and most common option of all dual camera systems - telephoto. In this design, the primary module is connected to a second sensor with a telephoto lens. Telephoto is the exact opposite of a wide-angle camera system. It actually allows you to zoom in only on the subject being photographed, and not on the entire scene.

Since the release of the iPhone 7 Plus (the first Apple smartphone with a dual camera), manufacturers have turned their attention to the telephoto lens as a second camera for branded smartphones. Telephoto currently offers 2x optical zoom, meaning the secondary sensor in such a system has twice the focal length. OPPO unveiled an innovative dual camera system with a record 5x optical zoom at MWC 2017 in Barcelona, ​​but this solution is still far from commercial release.

Wide-angle (top) and telephoto (bottom) on iPhone 7 Plus

Portrait mode with studio lighting feature on iPhone 8 Plus

What are the disadvantages

Because of this difference in the characteristics of the dual cameras, there is a noticeable discrepancy in quality when it comes to shooting with a specific module (wide-angle only or telephoto only). However, the level of photo capabilities that mobile devices like the Galaxy Note 8 or iPhone X offer today is incredibly high.

What are the prospects?

The development of smartphone cameras over the past couple of years has truly surpassed all expectations. There is no doubt that dual camera technology is the future of mobile photography. Already now they are equipped not only with flagships, but also with middle-class devices, as well as even some budget models. New life for black and white photographs, portrait mode with a blurred background straight from DSLRs, high-quality lossless zoom, higher detail - all this can now be done by smartphones thanks to dual cameras.

The trend of recent years is the presence of a dual main camera on a smartphone.

Some manufacturers have gone even further: some began to equip phones with dual front cameras, others began to use triple modules and other modern technologies. Why does a smartphone need a dual camera, does it make sense, what advantages and functions does it offer? Let's try to figure it out in this article.

Operating principle

A camera with two sensors works on the same principle as with one - light passes through the lens, hits the matrix, and the processor processes and reads the information to then convert it into a photo or video. A dual camera works on the same principle, only it has two matrices at once that work independently of each other. The final image is “glued” together by the processor from two images, so the final result depends not only on the photo modules, but also on the chipset. The more powerful and advanced the processor, the better the final result.

Also extremely important for devices with dual cameras are the software algorithms and functions of the secondary module. The latter are determined by the manufacturer independently, but in most cases, the presence of a dual camera in a phone opens up many advantages and additional functions.

Bokeh effect

One of the most popular and sought-after features is the bokeh effect, thanks to which you can blur the background in a photo. This way you can create a photo that is close to that of an SLR camera. In this case, the additional camera module is used to determine the object in space, and the smartphone does the blur at the software level.

Photo with bokeh effect on Huawei P20 Lite

Improved detail

Manufacturers often use double photo modules, one of them has a lower resolution (number of megapixels) but a larger aperture, the second, on the contrary, is equipped with a lower aperture ratio but a higher resolution. This combination ultimately results in images with stronger, clearer detail.

Optical zoom

The presence of a regular and wide-angle sensor gives another advantage to dual cameras. Thanks to this combination, you can enlarge photos with virtually no loss of quality. The fact is that the second module is equipped with optical zoom. If previously you had to approach the subject to create a beautiful shot, now you can simply press a button and take a beautiful photo. Unfortunately, not all devices on the market are equipped with this option.

Changing Focus

Some manufacturers have smartphones whose camera modules can be used to take pictures with variable focus. This allows you to manually change the focus point of a finished photograph. Also, many gadgets are equipped, which provides accurate and instant focusing.

Do you need a dual camera for your smartphone?

It’s difficult to definitely call her superfluous. The presence of an additional main camera module makes the device more attractive compared to its competitors. Smartphones like these can take wonderful, high-quality pictures, and an excellent addition is the presence of optical zoom and other important functions.

As mentioned above, manufacturers did not stop at the dual camera, but went further. Not long ago, Huawei introduced a new flagship smartphone equipped with .

One of the most recent trends in smartphones is the installation of a dual main camera. The operating algorithms of this module are different, but usually the main matrix is ​​used for shooting, and the second one helps improve the photo in various ways. But the way to implement this functionality differs, depending on the manufacturing company.

Today in our review are the following models with a dual camera:

This selection is dedicated to smartphones from the end of 2016 - beginning of 2017, which are equipped with two cameras. It does not include all devices that have a dual module, but only those that are most interesting in their price niches or are distinguished by some unusual approach to implementing the functions of the photographic subsystem.

LeEco Cool 1

Among the cheap two-chamber new products, LeEco Cool1 should definitely be noted. LeEco Cool1 has a dual camera. It includes two 13.0 megapixel sensors: one monochrome and one color. According to the manufacturer, due to this structure it is possible to obtain much higher quality photographs.

In addition, the camera application provides a special additional SLR mode (as DSLR cameras are often called). In photographs taken with it, you can change the level of background blur after the fact, or move the focus point. The resolution of the front module is 8.0 megapixels.

Doogee Shoot 2

However, there are more affordable dual-camera phones out there. For example, Doogee Shoot 2 costs about 6,500 rubles if you order it from your homeland. The second generation model has become somewhat more affordable thanks to a smaller screen and a different processor. At the same time, the device received a more capacious battery, a 360-degree fingerprint sensor, Android 7.0 and a dual camera with a 2x optical zoom option, which, according to rumors, was created almost in partnership with Huawei.

In terms of hardware, the smartphone with a dual main camera, Doogee Shoot 1, is not far from budget smartphones. 16 GB of memory and quad-core MediaTek MT6580 processor with a frequency of 1.3 GHz. The display corresponds to a higher class: 1280x720, 5 inches, IPS. Battery capacity - 3,360 mAh.

Leagoo M8 Pro

According to Samsung, 92% of users take photos with their smartphone. At the same time, 36% choose a device based on camera quality. It is for this group of people that Leagoo has released a re-release of the M8 model. The new M8 Pro has a dual 13-megapixel camera with monochrome and color modules that captures photos with bokeh effects and increased detail.

Photos are saved to a built-in 16 GB storage device, and the smartphone has support for memory cards. You can view videos and photos on the 5.7-inch IPS display, and the 3,500 mAh battery will allow you to do this for a long time.

AllCallBro

AllCall Bro is made in an all-metal case from high-quality aircraft aluminum. Most of the front side of the device is occupied by a 5-inch IPS screen with a resolution of 1280x720 pixels, which is manufactured by the Japanese company Sharp and covered with 2.5D glass. It features wide viewing angles up to 178 degrees and vibrant colors. This allows you to watch photos and movies with friends, which once again confirms the name of the device.

The main feature of AllCall Bro is its dual main camera. An eight-megapixel Sony sensor is responsible for the shooting itself, while a second 2-megapixel sensor is used to collect depth of field data. This makes it possible to activate a special shooting mode so that the background is blurred and all attention is focused on the main subject. On the front side, there is a 2-megapixel front-facing camera for video calling and selfies.

Bluboo D1

A few weeks ago, Bluboo introduced its new smartphone Bluboo D1. The main feature of the new product is the dual main camera. It is represented by a combination of a 2-megapixel additional and eight megapixel main sensors. This allows you to change the focus point on the finished photo, as well as get a photo with a bokeh effect.

Xiaomi Mi6

April was marked by the long-awaited and high-profile premiere of the new flagship Xiaomi Mi6. It has been noticeably modified; all the “filling” is placed in a high-quality glass case with a stainless steel frame. There is 3D glass installed on the back and front, which is curved along all edges.

The second innovation is a dual front camera module with a resolution of 12 and 12 megapixels. There is four-axis optical stabilization, as well as the possibility of 2x optical zoom without loss of quality. The Xiaomi Mi6 smartphone will be able to take good pictures with the bokeh effect.

ZTE Nubia Z17 mini

As last year, ZTE presented a mini-version of the future flagship of the Nubia line significantly earlier than the flagship itself. ZTE Nubia Z17 mini is equipped with two 13-megapixel Sony IMX258 sensors with full optical stabilization. One of the device’s cameras is monochrome, and the second shoots in color.

The user can manually adjust the aperture in the range from f/1.0 to f/16.0 in order to change the level of background blur. The front camera shoots with a resolution of 16 megapixels, captures images with f/2.0 aperture, and also has a fairly wide viewing angle of 80°. On the front there is a 5.2-inch Full HD display with a 1500:1 contrast ratio, and underneath there is a 2950 mAh battery that charges very quickly via a USB Type-C connector.

AGM X1

We are already accustomed to the fact that secure smartphones look very unattractive and have mediocre characteristics. AGM X1 was a very pleasant exception: a 5.5-inch Super AMOLED screen with Full HD resolution, 4GB of RAM, an eight-core Snapdragon 617 processor clocked at 1.5 GHz, expandable internal memory and a capacious 5400 mAh battery with support for very fast charging. Quick Charge 3.0.

The case is made of an unusual material for smartphones - high-quality titanium alloy. It is protected according to the IP68 standard from dust and moisture. The fingerprint scanner unlocks the smartphone in just 0.2 seconds, even when your hands are covered in water. Another feature of the smartphone is a dual main camera with a resolution of 13 megapixel modules. The camera app launches in less than half a second and can take photos with a bokeh effect. Thanks to a very impressive battery, the AGM X1 works normally without recharging for up to three days.

Honor V9

An interesting gadget, Honor V9, was released under the Honor brand. Thanks to its dual camera and laser focusing mechanism, the device can create three-dimensional images that can always be printed on a 3D printer. Both smartphone cameras have the same resolution - 12 megapixels, but one of the sensors is color, the second is monochrome. The front camera resolution is 8 megapixels.

Honor V9 is equipped with a 5.7-inch screen with a resolution of 2560x1440 pixels, a powerful eight-core Kirin 960 processor, as well as 4/6 GB of RAM and 64/128 internal memory. Despite the rather thin body with a thickness of 6.97 mm, the engineers managed to equip the device with a capacious 4000 mAh battery. The device runs on Android 7.1 Nougat OS with EMUI 5.0 shell.