Since the camera appeared on mobile phones, mobile phone manufacturers have never stopped competing for imaging effects. In addition to the increasing number of sensors and pixels, other functions of the camera must be enhanced to stand out. Now let's make an inventory of the auxiliary focusing system recently used by the flagship mobile phone on the camera.
If you want to take a picture with clear image, the first condition is not how good the photosensitive elements or how high the pixels are, but that you must be able to focus accurately. The earliest mobile phones can only use some fixed focus cameras, so they can't focus accurately in many scenes. If you want to focus, you have to "manually" focus through the distance of your mobile phone. However, the appearance of auto focus has completely broken this dilemma.
However, although the camera can focus automatically, in the process of use, especially in some dark scenes, or scenes with too single color, you will find that the success rate of focusing is very low, focusing is very slow, and sometimes you can't focus. In order to further enable users to have a better focusing experience, major mobile phone manufacturers have repeatedly come up with strange tricks to solve this problem.
More powerful processing chip
This is more commercially available for many factories, including Apple and Samsung. In the process of camera imaging, in order to process photos faster, a fast enough processor is also necessary. This problem can be found intuitively by comparing phones with different processors at the same resolution. But in addition to the processor, a good image processing chip (ISP) is more important for faster processing focusing time and imaging speed. Some, especially most domestic mobile phone manufacturers are basically using the ISP integrated in the mobile phone processor, so it is said that the domestic mobile phone stack hardware is often not enough. However, some foreign mobile phone manufacturers like to use specially optimized ISPs to improve the processing speed of cameras, typically Apple and Samsung.
In fact, Apple's official website has stressed that the ISP developed by them together with the iPhone 5S, an 8 megapixel camera, can make the camera focus faster and more accurately.
For Samsung, the flagship models that use their own Exynos processors basically use Fujitsu's ISP to improve the camera's imaging ability. Because of this, there is also a tradition that the imaging effect of the Exynos version of the Samsung flagship will be better than that of the Qualcomm version.
However, compared with Samsung, it is not enough to simply use an excellent ISP. On the Galaxy S5, Samsung's latest flagship machine, Samsung uses its own ISOCELL sensor. The area of this sensor has been improved to 1/2.5 inch and the resolution has been improved to 16 million pixels of 16:9. According to the official announcement of Samsung, ISOCELL can isolate pixels of each color compared with BSI sensor, improve the light capture capability of the sensor, and reduce pixel crosstalk by 30%. In addition, it also adds phase detection technology to assist focusing, and can focus successfully in 0.3 seconds as soon as possible. However, phase focusing has a high requirement for light. When the light is sufficient, phase focusing will be very decisive and fast, and there is no need to move back and forth to detect the best focus. However, the focusing speed will be greatly reduced at night, but of course, the ability to take night pictures with mobile phones without manual function is always limited, and it is true that mobile phones are rarely used to take night pictures.
Closed loop motor
Speaking of the closed loop motor, the first one in China should be the vivo X3. Compared with the ordinary VCM motor, the closed-loop motor has higher focusing accuracy, faster focusing and lower power consumption, especially under the large aperture. The working principle is to first save several frames in the preview screen to the memory in real time. When the shutter is pressed, the system will automatically read the clearest frame and save it as the final image. This enables it to have a faster focusing speed and imaging processing speed. In practice, the focusing speed is also relatively good, but after all, domestic manufacturers have not been able to compare with foreign mobile phone manufacturers in terms of software and image processing chips, so their imaging ability is not very good.
Laser assisted focusing
Once you see this function, I believe you all know that the next thing to say is LG G3. After LG used its own 13 million pixel optical anti shake lens in G2, the photo taking effect really improved (of course, the G Flex that tested the water later did not use this lens, so it was poor). Since the right way has finally been found, LG will not give up. It also uses 13 million pixels with optical anti shake on its latest flagship, G3. It is exaggerated that G3 also has a laser assisted focusing system, which is a small black block on the left of the camera, containing a laser transmitter.
When starting the camera focusing, the laser focusing module will also start up to help the camera focus quickly and accurately. Of course, the laser emitted is invisible infrared light, but we can still capture it through the camera. According to the official introduction of LG, G3 will emit a conical laser beam from the laser transmitter when shooting, and then the mobile phone will judge the distance of the object according to the time of the laser reflection back, so as to complete focusing. The principle of this system is similar to that of the bat sonar system. The laser focusing is only one of them. There are still traditional focusing modes and face focusing modes. The system will use the best focusing mode in the current environment to shoot. For example, if the laser focusing fails in some scenes, the traditional mode will be used for focusing. LG claims that the laser auto focusing time of G3 is 276 milliseconds, which should be a promotional selling point.
Since we have got the LG G3, from the practical use, the focusing speed is really fast when the light is enough. However, in the case of shooting night scenes, the performance is quite ordinary, and there is no obvious function of fast focusing, and it is far from the 276 millisecond focusing speed claimed by LG.
After reading the above brief introduction, you should be more clear that camera imaging is actually a very profound knowledge, but there is a wide range of focus that can be discussed. It involves too much knowledge in all aspects, and the article can only give a brief introduction. If you want to further study, it may not be so easy. However, it is certain that in the future, the camera functions on mobile phones will become more and more abundant, and the focusing effect and speed will also be improved. At present, the emergence of these focusing auxiliary systems is just the beginning.
