The past and present of mobile phone cameras are like a game of PlayerUnknown's Battlegrounds

　　When it comes to PlayerUnknown's Battlegrounds, some people may still be unfamiliar with it, but when it comes to "Chicken Dinner", many people are probably familiar with it. I am also a fan of the game, and when I was thinking about this article, I suddenly had an idea to compare the past and present of mobile phone cameras to a game of Chicken Dinner. There are many surprising similarities. (Of course, some places may be far-fetched, but for the sake of understanding, please just laugh it off.) Let's follow the editor of Mobile Portable to learn about the relevant content.

 The past and present of mobile phone cameras are like a game of PlayerUnknown's Battlegrounds

　　For example, at the beginning of the game, as soon as you land after parachuting, the first thing you think of is to quickly find a gun, whether it is a pistol or a shotgun, to solve the problem of whether there is a gun or not, so as to survive on the battlefield (market). When mobile phones just began to popularize cameras , the problem of whether there is a gun or not must be solved first; then, with the upgrading of guns ( camera photosensitive elements), the caliber of bullets became thicker (pixel size) and the lethality (image quality) gradually increased; but having a gun (photosensitive element) alone is not enough, you also need a grip (anti-shake component) and a zoom lens (zoom lens) to ensure that you can win in encounters, improve your survivability, and ensure that you will eventually reach the circle of destiny (both word of mouth and market). How about it? Does it sound reasonable? Then the exercise will start immediately, and get ready to parachute!

　　Landing: Find a gun first

　　At the beginning of PlayerUnknown's Battlegrounds, when the protagonist lands on the battlefield, the first thing he usually does is to find a gun, even though this gun may not be his favorite. But in order to prevent himself from being attacked by others without any weapons and being killed (the game character will turn into an equipment box when he dies), he will pick up even the slightly useless rifle without hesitation.

The first mobile phone with a camera - Sharp J-SH04

　　When mobile phone cameras first became popular, they also experienced a period of somewhat useless parameters. In September 2000, the world's first mobile phone equipped with a camera was born - Sharp J-SH04. Its camera pixel was only 110,000 pixels, not even enough to print a one-inch photo.

　　Without autofocus, beauty, or flash, it was difficult to win the market's attention. However, it is worth noting that the photosensitive element of the mobile phone camera at that time was still made of CCD, rather than the commonly used COMS at present, because the latter technology was not mature at that time.

　　Although the market performance of the first camera phone was not as enthusiastic as expected after its launch, adding a camera module to the phone became the mainstream trend of mobile phone development in the following years.

　　In 2003, the autofocus module was born

　　In 2003, Panasonic released a mobile phone with a unique rotating design, the Panasonic P505iS, which can rotate 360 ​​degrees sideways and 180 degrees backwards to take selfies. Obviously, this is a mobile phone that focuses on camera functions. The most eye-catching thing about it is that it is equipped with an autofocus function for the first time. In the photo mode, by half-pressing the shutter button on the side of the body, the autofocus function will automatically focus on the subject in the middle, and you can shoot directly by pressing it.

Panasonic P505iS

　　If the camera sensor is compared to a gun, then the autofocus module is like the crosshairs on the gun. It solves the problem that early cameras can only fix the focal length at infinity, resulting in blurry images of close objects, allowing mobile phones to adapt to more shooting scenes and bring clear pictures. Nowadays, almost all smartphones are equipped with autofocus modules on their rear cameras.

VCM autofocus module structure diagram

　　However, it was not easy to make mobile phones autofocus at that time. Due to the size of mobile phones, people could not transplant the traditional bulky camera focus module to mobile phones. So it was necessary to create a focus module for mobile phone cameras. The final solution was a metal cover covering the photosensitive element. The lens was not completely fixed inside the cover, but was fixed with a small spring to allow it to move up and down.

　　The metal coil is wound around the lens module, and magnets are designed at the corners of the metal cover to provide a magnetic field. When the current passes through the coil, the coil wound around the lens module moves due to the force according to the principle of electromagnetic induction, thereby achieving the purpose of focusing. This technology is called VCM voice coil motor. To date, nearly 80% of mobile phones still use this focusing component.

The principle of contrast focusing

　　However, it is not enough to have a focusing component. How to adjust the focusing module and fix it in the position we need is also a problem that manufacturers need to solve. The most stupid contrast focusing method was used in early mobile phones. The principle is to apply different currents to the lens group to adjust the lens position, thereby adjusting the focal length, and then find the lens position with the maximum contrast according to the contrast change of the picture at the focus, that is, the accurate focusing position.

　　Try: Finding the market appetite

　　In the era of feature phones, the impact of software on users was far greater than it is today. Therefore, if mobile phone manufacturers want to create product differentiation, hardware is the only way out. When mobile phone manufacturers realized that taking pictures can bring a better user experience to users, they began to explore camera modules that are more suitable for mobile phones. However, in the early stages of development, it was difficult for the industry to take into account all the factors that affect shooting quality, such as pixel count, focus, fill light, anti-shake, zoom, etc., so we see many products on the market that only take into account one aspect of the capabilities.

　　2004, the first optical zoom phone

　　In PlayerUnknown's Battlegrounds, if the enemy is far away from you, it is difficult to hit it without a zoom lens, and you can only watch it disappear from your sight. In real life, if the mobile phone does not have a zoom function, it will also be unable to do so in some scenarios, such as sitting in the last row of the classroom and taking a photo of the teacher's notes on the blackboard...

Sharp V602SH with 2x optical zoom periscope lens

　　In May 2004, the world's first optical zoom mobile phone was born. It was the Sharp V602SH with a 2x optical zoom periscope lens. However, the 200W pixel level still limited its practicality.

　　In July 2004, following the Sharp V602SH, Samsung launched the SPH-S2300 for the Korean market. It had a 3.2-megapixel camera , supported 3x optical zoom, autofocus and some manual settings, and a maximum ISO of 400. The retractable camera made people think it was a camera with a call function.

　　Nokia was certainly not to be outdone and in 2006 launched the N93, which could achieve 3x optical zoom.

　　In 2005, we tried to cooperate with traditional optical imaging giants

Nokia N90 is the first mobile phone to use Carl Zeiss certified lens

　　I don’t want to comment too much on the industrial design of the Nokia N90 launched in 2005, because the dual-shaft design is so special. But another great achievement of the phone in terms of photography is that it uses a Carl Zeiss certified lens. Nokia pioneered the cooperation between mobile phone manufacturers and traditional optical imaging giants. Although the image quality presented by the 200W pixel of the phone did not become outstanding because of the high-end lens, it and its descendants have gained market recognition by virtue of the halo of the master optical imaging giant.

　　If I were asked to match this configuration with an equipment in PlayerUnknown's Battlegrounds, I think the ghillie suit that can only be obtained in airdrops would be more appropriate.

　　2006, the first xenon flash phone

　　The function of the flash is to allow the phone to capture scenes that cannot be captured under normal circumstances, such as night scenes, dark rooms, etc. This is a bit like the grenade in the PUBG game. You know there are enemies upstairs, but the reality is that you are easily shot in the head when you go up the stairs. OK, that grenade solves the problem. However, if the LED flash is a grenade, the xenon flash is a bit like a dynamite pack... Although it is powerful enough, carrying one will take up half of the level 3 pack...

Sony Ericsson K790: The first Xenon flash phone

　　As the flagship product of 2006, the Sony Ericsson K790 is equipped with a 3.2-megapixel camera and is considered by the industry to be the first mobile phone equipped with a xenon flash. Compared with LED flash, it can provide more sufficient light in dark conditions. At the same time, the flash also has the red-eye reduction function that only digital cameras are equipped with.

　　The xenon flash unit on the mobile phone has been miniaturized, but it still takes up a lot of space.

　　It can be seen that equipping a better fill light component is Sony Ericsson's effort to improve the camera function of mobile phones, but from the product picture above we can see the disadvantage of this component - it is too thick. This is because the xenon flash not only includes the lamp body itself, but also includes a large high-voltage capacitor to supply power.

　　For a mobile phone, a portable product, if it loses its portability, it will inevitably be ignored by the market, so the sales of this phone are not good. In the history of mobile phone development, there are several products that use xenon flash, such as Nokia Lumia 1020, Lumia 928, etc. However, their thick body is destined to be unacceptable to mainstream consumer groups. It is precisely because of this that LED flash, which is lighter and more power-saving, will maintain its dominant position in the field of mobile phone lighting.

    Fierce battle in shrinking circle: high-end equipment all in action

　　PlayerUnknown's Battlegrounds is interesting not only because of the various powerful weapons, but also because of the tension created by the poison circle that shrinks the battlefield every once in a while. Because as the battlefield narrows, the chance of encountering enemies becomes greater. However, you must take the risk to run to the safe zone, because outside the poison circle, there is only one way to die.

　　If we say that from 2000 to 2006, it was the initial development period of mobile phone cameras. Mobile phone manufacturers could cram in optical zoom and xenon flash components by virtue of the size and low thickness requirements of feature phones. Then in 2007, a historic moment came - the birth of the iPhone. This is a product that subverted the operating logic of the feature phone era. It is light and portable, with a large screen and built-in APP social software, making mobile phone photography more important than ever. However, the thin and light attributes of smart phones limit the performance of the camera. Whoever can bring a better photo experience in a smaller size can survive more comfortably. The "poison circle" of the mobile phone industry began to shrink.

　　In 2012, optical image stabilization technology was born

　　In PlayerUnknown's Battlegrounds, one of the most popular rifles is the M416, because it is stable when shooting, allowing you to hit the enemy with every shot. However, this stability is not something you can experience when you first get the gun, but requires the support of accessories such as grips and tailstocks to reduce the recoil of the rifle's horizontal and vertical axes when shooting.

Lumia 920

　　In 2012, Nokia launched Lumia 920 equipped with Carl Zeiss certified lens and OIS optical image stabilization technology. This technology corrects the "optical axis offset" through the floating lens of the lens. The principle is that the gyroscope in the lens detects tiny movements, and then transmits the signal to the microprocessor. The processor immediately calculates the displacement that needs to be compensated, and then compensates the lens according to the shaking direction and displacement of the lens through the compensation lens group, using the principle of the VCM voice coil motor mentioned above; thus effectively overcoming the image blur caused by the vibration of the camera. This anti-shake technology has relatively high requirements for lens design and manufacturing, and the cost is relatively high.

　　The effect of the optical image stabilization function is quite obvious. Generally speaking, turning on this function can increase the shutter speed by 2-3 stops and reduce the chance of blurring when shooting handheld.

　　In 2012, the 4100W pixel mobile phone was born

　　Mobile phone pixels are like bullets in an automatic rifle in a game. If a magazine of bullets can hold more, your attack capability (image quality) will be significantly improved. The pixels in the mobile phone industry have been improving, because only higher pixels can bring more details to the image. Even CCD sensors were replaced by CMOS sensors, and one of the main reasons is that CMOS can bring a higher number of pixels.

Nokia 808 PureView

　　Nokia's exploration of camera functions can be described as being ahead of its time. In 2012, Nokia launched the 808 PureView, a phone with an astonishing 41 million pixels, a parameter that even SLR cameras can hardly match. Today, six years later, there is a phone with the same configuration, also using this as a selling point.

　　In 2013, Ultrapixel technology brought 2μ pixel size

　　In the field of mobile phones, the number of pixels and pixel size are two contradictory concepts. The pixel size is like the caliber of a bullet in a game. The larger the bullet, the stronger its lethality (image quality). However, as the caliber of the bullet increases, it will inevitably take up more space, so under the premise that the capacity of the magazine remains unchanged, the number of bullets loaded will decrease.

　　The same is true for mobile phones. Due to the thin and light size of mobile phones, the size of the photosensitive element cannot be made larger. Therefore, if high pixels are pursued, the area of ​​a single pixel can only be controlled smaller, generally around 1.2μ.

HTC One M7

　　However, HTC chose to increase the area of ​​a single pixel, so that a single pixel has a higher amount of light entering, so as to obtain a better night photography experience. On February 19, 2013, HTC released the new generation flagship smartphone HTC One M7. The phone is equipped with a self-developed Ultrapixel (abbreviated as "super pixel")  camera , the biggest feature of which is the 2μ super-large pixel, and the sensitivity is 300% higher than that of ordinary mobile phone cameras . Unfortunately, due to the high pixel size, the number of pixels in its camera is only 408W.

　　In 2013, the first dual-color temperature flash was born

　　We know that all high-end cameras generally use xenon flash as fill light device. On the one hand, it is because its light intensity is stronger. On the other hand, it is also because its color temperature is very close to the color temperature of sunlight, making it easier to control the white balance of the taken photos.

iPhone 5S

　　However, as the mobile phone industry enters the era of smart phones, the thin and light appearance determines that LED light source is the best fill light material. It has the advantages of energy saving and compact size. Although it is an objective fact that the brightness is not as good as that of xenon flash, the problem of color temperature can be solved by technical means. In 2013, Apple launched the iPhone 5S, which uses a dual-color temperature flash. It adjusts the light intensity of two flashes with different color temperatures to improve the color temperature level of the shooting environment, and has achieved true color restoration of the film. From the follow-up of friendly companies, it can be seen that this is a mature and effective solution.

　　In 2014, laser focusing technology and phase detection focusing technology (PDAF) were widely used in mobile phones.

　　In the previous article, we regarded the focusing technology as the crosshairs in the PUBG game. If the initial contrast focusing is the crosshairs of the machine aiming, then the laser focusing and phase focusing technologies can be regarded as red dot or holographic sights, which can bring faster aiming speed (focusing speed) and can adapt to more environments. (Dark light environment)

　　At the MWC in February 2014, Samsung launched its flagship Galaxy S5, which was the first to be equipped with PDAF phase focusing technology. The image sensor used in this technology sacrifices some pixels in the photosensitive area. These pixels are called masked pixels and are used in pairs. The distance between pixels, combined with their relative changes, can help the system determine how far the lens needs to move for accurate focus, just like the human eye can distinguish the distance of objects.

　　With this focusing system, the focus of the mobile phone does not need to adjust the focal length back and forth (commonly known as pulling the bellows) like the traditional contrast focusing to determine the correct focus. In short, this technology can significantly improve the focusing speed. Later, Apple also equipped the iPhone 6 with this phase focusing technology, named Focus Pixel.

LG G3

　　In May of the same year, LG released its 2014 flagship LG G3. What was eye-catching was that the LG G3 was not only equipped with a dual LED flash, but also a sensor with laser autofocus function. The sensor would emit a cone-shaped laser beam from a window on the same side as the camera, and repeatedly judge the distance of the object based on the length of time it takes for the laser to reflect back, and then complete the focus.

　　This technology enables the focusing speed to reach 276 milliseconds, which is even faster than a human blinking. In addition, since it uses active emission focusing technology, it can also provide a fast and accurate focusing experience in low-light environments. However, it also has a disadvantage, that is, because the power generated by the laser is limited, it can only focus on nearby objects.

　　In 2014, ISOCELL deep trench isolation technology

　　When it comes to the manufacture of mobile phone image sensors, Sony's IMX series may come to mind first, but Samsung also plays an important role in this field. When Samsung released the S5 in 2014, it equipped the camera sensor of the phone with ISOCELL deep trench isolation technology.

Samsung Galaxy S5

　　This technology is based on BSI (back-illuminated sensor) technology, and focuses more on reducing interference between pixels. Compared with BSI technology, ISOCELL technology can reduce pixel crosstalk by 30%. By forming a physical barrier between pixels, the interference problem between pixels is avoided, allowing pixels to absorb more photons, obtain better photo effects, and thus improve image quality. In addition, in terms of design integration, ISOCELL can also further reduce the camera module, making the phone thinner and lighter.

　　Perhaps, after reading all of this, you may feel that this technology is somewhat familiar. That is probably because you have seen the camera performance of iPhone 6s. Because it is also equipped with this technology, and compared with Samsung's relatively low-key, Apple seems to be more willing to use this technology as the focus of its camera promotion. However, the release time of this phone was 2015, just like the phase focus technology, it was one year later than Samsung.

　　Deadly Poison Circle: A Test of Fate

　　In the later stages of PlayerUnknown's Battlegrounds, as the poison circle gradually narrows, not only the opponent's equipment has reached a very high level, but the power of the poison gas outside the circle has also become extremely powerful. Therefore, the only choice left for players is to take every step carefully.

　　After 2016, as the seasonal craze brought about by the popularity of mobile Internet and smartphones gradually subsided, the competitive pressure faced by mobile phone manufacturers became increasingly greater. If there was a mistake in product positioning, it might mean a serious decline in reputation and even a crisis of fate. Many mobile phone manufacturers were eliminated by history under such circumstances.

　　In the development of mobile phone cameras , the introduction of new technologies has been relatively slow in the past two years, but the ambition is huge, because mobile phone manufacturers have already set their sights on competing in the field of professional digital cameras...

　　Dual-camera technology: image quality, depth of field, and zoom

　　I thought of a classic sentence: there is nothing that a single camera can't do. If there is, it's another camera. Dual-camera technology was actually applied in the mobile phone industry in 2011, but it took the wrong path at that time. It took the 3D shooting route, but the experience was very poor, so it was quickly eliminated.

　　Nowadays, dual cameras have been divided into several factions after development, namely, the black and white color dual camera represented by Huawei mobile phones, the zoom dual camera represented by iPhone Plus models, and the three factions of a high-parameter main camera plus a poor auxiliary camera with parameters only for blurring. Obviously, the first two are the most technically advanced. The black and white camera in Huawei's black and white color dual camera has a stronger ability to receive light due to the removal of color filters, which can bring richer and sharper pictures. Through algorithms, it is combined with the color information of the color camera, thus retaining the advantages of both cameras. And it supports large aperture mode.

　　The dual-camera of the iPhone Plus model uses two cameras with different focal lengths to achieve a 2x optical zoom capability. And through the dual-camera algorithm, the iPhone also has its own large aperture mode, but it is called "portrait mode".

Huawei P20 Pro

　　The recently launched Huawei P20 Pro mobile phone even adopts a three-camera solution, which adds a telephoto lens to the original solution, allowing its own products to have optical zoom capabilities.

　　Stacked photosensitive elements: slowing down time

　　In addition to the aforementioned factors such as stability, bullet size, and magazine capacity, another important factor that determines the quality of a gun in PlayerUnknown's Battlegrounds is the rate of fire (the number of bullets fired per unit time). The difference in total damage between firing 240 rounds per second and 960 rounds per second is definitely obvious.

Sony XZ Premium

　　In the field of mobile photography, slow motion video has become a technology favored by manufacturers. Last year, Sony released a new generation of IMX400 series photosensitive elements. The biggest improvement of this series is the use of a stacked structure, which adds a layer of DRAM dynamic memory between the traditional photosensitive layer and the bottom circuit, so that the photosensitive element has the ability to shoot large amounts of data in a short time.

　　The specific data is that 960 frames of 720P resolution video can be recorded in 1 second. If this video is played back at normal speed, it is equivalent to slowing down time 32 times! Fleeting scenes such as bubbles bursting and bullets being fired will become clear and shocking in front of this technology. This technology was first installed on Sony's own XZ Premium.

　　Variable aperture technology: This is the ideal aperture solution

　　At the MWC in February this year, Samsung launched the S9 series of mobile phones. One of the major selling points of the phone in terms of photography is the use of variable aperture technology, that is, the aperture can be changed between F1.5 and F2.4. Some people may wonder, shouldn't the aperture of mobile phones be as large as possible? In fact, it is not the case, because the larger the aperture, the higher the risk of reduced image quality of the mobile phone lens, so you will find that the aperture parameter of the iPhone is not the highest among mobile phones of the same period.

Samsung S9 plus

　　However, the significance of large aperture on mobile phones is mainly to reduce exposure time by increasing the amount of light entering, and increase the probability of filming in dark environments. But if you want to ensure better image quality in bright environments, you need to reduce the aperture. So I think variable aperture is the best aperture solution for mobile phones at present.

　　About the future: There is no chicken dinner on the battlefield of mobile phone photography

　　Looking at the development of mobile phone cameras over the past 18 years, we find that its functions are closely related to the development stage of the mobile phone. In the era of feature phones, mobile phones were only used as a communication tool. Although they were important, communication was the core, so the development of cameras was just icing on the cake, and more of the existing camera technology was transplanted to mobile phones; however, in the era of smart phones, with the prevalence of mobile Internet and social software, cameras have become an important component for mobile phones to create data and value. At this time, it has received special treatment tailored to it, with large aperture, high pixel, optical image stabilization , laser focus, etc., and a number of new technologies are only for it; later, with the decline of the mobile phone update trend, mobile phone manufacturers need to launch real-life camera products in order to protect themselves to meet the increasingly picky needs of consumers.

　　However, in the battlefield of photography, there is no chicken, only a constant stream of new airdrops and new enemies. However, on the road of chasing airdrops, some manufacturers may become cannon fodder under the guns of others, while some manufacturers have obtained extremely powerful new equipment...

   The above is an introduction about the past and present of mobile phone cameras in portable mobile phones, which is like a game of PlayerUnknown's Battlegrounds. If you want to know more related information, please pay more attention to eeworld. eeworld Electronic Engineering will provide you with more complete, detailed and updated information.