What’s good about periscope lens? What’s the difference?

Many years ago, in order to be thinner, the card camera developed the “periscope lens”. The representative product is Sony’s T series card camera, which has become a hot product in the market as soon as it comes into the market. One of the representative works: Sony T900, which was released in 2009, was also a high-end product of T series at that time. It was equipped with a 4x optical zoom lens and a 1 / 2.3-inch 12 megapixel sensor on a 16.3mm fuselage, as well as the largest touch screen and stereo pickup in the camera at that time, which were the mainstream configuration of high-end card machines in the next few years. In a word: Sony uses exclusive “black technology” to let all users know that the principle camera can be so thin and super powerful! < / P > < p > although the above parameters seem very water now, we should know that it was an era when CMOS had not become the mainstream and CCD sensor still had a place. At that time, Sony took out these parameters, and there was no rival in the market. < / P > < p > back to the main topic, although periscope lens has brought effective space optimization, this architecture has always been inadequate, that is: image quality. This is due to the “periscope” text of the periscope lens. It can be seen from the words that this structure was born to provide vision for the personnel in the submarine. In other words, it is not a product of pragmatism designed for photographing. < / P > < p > as for why the picture quality is insufficient? In short, there are two words: refraction. Elementary school physics class will tell us that the working principle of periscope is to install lens in the 90 degree bending tube, so that the light can be seen through refraction. But why does refraction affect the quality of the image? Let’s talk about the story first. The periscope is a design that can change the direction of light. As early as 1685, it was discovered by German monk John thunn and made into a SLR darkbox. However, the level of time science was not high, so the reflected things were very vague, so people at that time did not imagine what the use of this thing was. It was not until the middle of the 18th century, that is, the Renaissance, “glasses” began to become popular. Finally, some people found that after adding special lenses to this thing, the clarity of the reflection picture could be improved. It was only then that painters found that the SLR darkbox could be used as a tool for sketching from life. < / P > < p > at this time, camera, film and other technologies are also developing at the same time, but the camera at this time is either a huge and large picture, although it can capture the scene and the picture is what it is; or it is a side axis camera like Leica in Germany, although its volume is much smaller, because the viewfinder and lens are separated, the photos taken and the scene taking are not The experience of “what you see is not what you get” makes many people feel uncomfortable. It was not until 1884 that the first SLR camera was invented by Carlyle Smith of the United States through the periscope principle, which achieved a small size and “what you see is what you get” shooting experience. < / P > < p > do you think that the above mentioned has little to do with the periscope? In fact, it is not because the development of science and technology is to constantly let people have a better life. The emergence of SLR makes photographers have more pursuit and ideas, one of which is to continue to improve the clarity of shooting. So, in 1949, Contax finally launched the world’s first SLR camera with pentaprism, and let the photographer feel the experience of “clear, bright and accurate”, without the embarrassment of upside down, left and right when shooting. This also established the longest professional camera framing structure in the history of photographic equipment. < / P > < p > why is the viewfinder bright and clear after using a prism? Compared with the mirror reflection, the reason is that the reflection of the mirror is much better than that of the mirror in the transmission of light. < / P > < p > take a very common example, that is, the five mirror viewfinder in the SLR camera. This structure is widely used in entry-level SLR cameras, and is characterized by light weight and low cost. However, we all know that the viewfinder of the entry-level SLR is much dimmer than that of the professional SLR, and it is more or less a little “false”. This is because the cavity of the pentahedron mirror is empty and there is air in the middle, which will damage part of the mirror during light conduction. On the other hand, the silver layer on the electroplated mirror also has wrinkles that can’t be seen by the naked eye, which will further scatter the broken light and cause secondary damage in the cavity. The function of pentaprism is to minimize these effects and ensure the quality of light transmission. < / P > < p > this is the reason why the image quality is reduced because of refraction. The topic goes back to the periscope group. Starting from Sony T series, all products with higher positioning adopt prism as the refraction surface, while entry-level products use the mirror as the refraction surface. However, due to the technical limitations of the previous DC cameras, the image quality gap between the two is not very large. However, the ASUS Zen phone zoom, launched in 2016, took the lead in adopting a biprism refraction structure, and at the same time took into account the image quality and the true and true Triple Light zoom. Although it was a small number of products, it did give me a great surprise at that time. It also proves the optical advantage of prism to image quality. < / P > < p > let’s take a look at the periscope sets used by several mainstream flagship mobile phones. First of all, Huawei P40 Pro uses a prism as a periscope mirror group of refraction components. On this basis, an optical anti shake structure is added. The prism is responsible for the jitter compensation in the up and down directions, and the rear lens is responsible for the displacement compensation in the left and right directions, thus realizing the most basic two axis anti shake structure. Therefore, the image quality of this periscope mirror group is guaranteed. Besides, Huawei also configures the EIS anti shake algorithm to simulate the anti shake action of three axis rolling alignment of XYZ axis. That is to say, the optical and electronic anti shake parts are used to achieve the near five axis anti shake effect. However, there is a problem with Huawei P40 Pro mirror group, that is, the lens area causes the thickness of this mirror group to be larger, and the thickness of the mobile phone body also increases. In particular, the height of the protruding part of the mirror group is one of the more powerful mobile phones. Oppo find x2 pro, which uses a periscope structure similar to a prism, removes the upper and lower parts of the lens with larger area through D-cut technology, allowing the whole lens group to further compress the thickness without affecting the image quality. Therefore, the thickness of the mobile phone can still be maintained in an ideal state. < / P > < p > when it comes to periscope lens group, Huawei P40 PRO + has to be mentioned. This is the first design that uses 5 times refraction structure to achieve 10 times focal length and compress the lens group volume to the limit. The components responsible for refraction are three mirrors and one birefringence prism. Therefore, there is a problem here. As mentioned above, the more refraction, the greater the damage to light, and the greater the loss of refraction to light. However, Huawei has also made compensation, such as using nano scale mirror adhesion technology to make the mirror surface smoother and reduce the scattering index, and glass also uses it The material with higher transmittance reduces the light loss and scattering to the minimum. The high cost of this can be said to be the highest level among mobile phone cameras. < / P > < p > but it should be emphasized here that although the prism can reduce the influence of image quality degradation, it always has an impact. Only thanks to the status quo of the increasingly strong image algorithm to make up for these optical defects, such as a large number of consecutive frames derived from the image optimization algorithm, so that these problems can be well solved. < / P > < p > it’s time to return to the key topic. Now, the mobile phones equipped with periscope lens mainly have single prism structure and multi refraction structure. The cost of these two structures is not low, and they are the type with high requirements for production technology. Therefore, the mobile phones that can produce good periscope group are basically products with the level of 4000 yuan or above, and the photography level is not low, So the difference of the thickness of the body, the thickness of the lens and the optimization of the lens are the same. In addition to oppo and Huawei, vivo and glory are equipped with periscope telephoto cameras in their flagship models. It can be said that most mobile phone manufacturers are gradually recognizing periscope telephoto lenses. Let’s take a look at the performance of these manufacturers in periscope telephoto lenses. < / P > < p > as the first official commercial periscope telephoto manufacturer, oppo has a lot of technical precipitation in periscope telephoto lens adjustment. On the basis of Reno 10x zoom version, oppo makes the flagship find series have more say in shooting. After all, find The screen of the X2 series is better, so the requirements for the shooting ability of the mobile phone are also improved, because you can see more details from the screen. < / P > < p > through the OIS optical anti shake and EIS hybrid anti shake double anti shake, the performance of find x2 pro in the long focus end is impressive. When shooting distant objects, it also has a very strong analytical power, even in the 10 times focal length, it can accurately restore the dark details, and the overall picture is still clear and bright. < / P > < p > next, Huawei is equipped with a special ryyb array sensor on the main camera, which is more sensitive to light. Due to the special arrangement problem, the color is different from the traditional RGB array sensor. In the case of periscope telephoto lens, the actual color is thicker for you. Of course, this is just a matter of color choice for mobile phone manufacturers, which does not affect their daily use. In addition, the image ISP chip of Kirin 990 on Huawei P40 Pro has further improved the film yield of this periscope telephoto lens through AI imaging technology. Under the independent and unique technology, from the chip to the sensor is independent. Therefore, in terms of overall imaging and shooting experience, although it is periscope telephoto, its style and color prediction are different from others. < / P > < p > although the launch time of vivo equipped with periscope telephoto lens is a little bit later, the performance of vivo X50 pro on periscope telephoto lens is no worse than that of other manufacturers with better periscope telephoto lens solutions and vivo’s own algorithm. With the support of snapdragon 765G independent image ISP, there is no difference in style and white balance between vivo X50 Pro telephoto lens and the pictures taken by the main camera. What’s more, with the powerful HDR algorithm of vivo, vivo X50 Pro can still maintain the hierarchical sense of the picture in the case of large light ratio. < / P > < p > finally, the glory 30 series model, through the special algorithm support, glory 30 can carry out the secondary deep processing of the image captured by the periscope lens, so as to obtain better and more realistic visual effect. In practical use, glory 30 has similar performance with other brands in terms of picture details or background blurring. In addition, with its low price, it is still quite good for users who want to experience periscope telephoto lens

Author: zmhuaxia