Performance, photography and battery life have become the troika that promotes the development of smartphones. Among them, chips represented by Kirin 9000 and Snapdragon 888 can give mobile phones the most powerful performance power; the emerging 120W fast charging technology is enough to make up for the shortcomings in battery life; under the implementation of the concept of "the bottom level is overwhelming" , the image quality of the main camera is also rising steadily, but how to make smartphones "see further" has become a pain point for countless mobile phones that mainly focus on taking pictures, because only periscope telephoto lenses can allow smartphones to see further at any time. Play the role of "telescope".
Tracing the development of periscope lenses
In the field of smartphones, periscope lenses can be traced back to the ZenFone Zoom released by ASUS at the end of 2015, but its periscope lens It uses a multi-lens module that can be displaced internally, and the focal length can float between 28m~84mm, which means it can perform optical zoom from 1X to 3X, and it is a "periscope zoom lens".
Starting from Huawei P30 Pro and OPPO Reno (10x zoom version) in 2019, "periscope fixed-focus lenses" have become popular in the smartphone field, and ZenFone Zoom's "periscope zoom lens" "Compared with the former, the internal lenses are fixed and can only take photos with a fixed focal length. However, this also results in a smaller module size, which can be placed in a thinner and lighter body.
Today, "periscope fixed-focus lenses" have become the mainstream of the market. Any mobile phone equipped with such a lens can at least obtain the equivalent of 5X optical zoom.
The mystery of the structure of the periscope lens
Traditional mobile phone lens, PCB circuit board, CMOS sensor, connector, bracket, infrared filter, focus motor and lens assembly The other components are arranged vertically. The advantage is that a larger-sized sensor can be placed on the bottom layer. Through a larger amount of light, the advantage of "a large bottom is overwhelming" can be fully utilized.
However, the shortcomings of this traditional structure are also obvious. The thickness of the lens module is fixed. If you want to increase the focal length, you must reduce the size of the sensor. Therefore, the focal length of the 1X main camera is generally between 20mm~25mm. time, and this vertical structure can only create a 3X telephoto lens of about 75mm at best.
The biggest change between the periscope lens and the traditional vertical lens is that the CMOS sensor is erected, the main internal components are arranged from vertical to horizontal, and an additional sensor is added at the position opposite the lens opening. A set of prisms that can bend the light path 90 degrees. The light comes in from the lens and is reflected by the prisms at 90 degrees before being transmitted to the sensor underneath.
The advantage of this design is that the Z-axis height (thickness) of the traditional vertical lens can be converted into the length of the X-axis, and a focal length of more than 100mm can be easily achieved while the thickness of the lens module remains unchanged. , obtaining an optical zoom capability equivalent to 5X.
However, periscope lenses also have inherent flaws, that is, there must be a certain amount of loss during the refraction of light, and this horizontally structured lens module takes up more space inside the phone. In Z While the axis height remains unchanged, it is still impossible to fit a larger CMOS sensor. The sensor size of most periscope telephoto lenses on the market is only about 1/3.4 inches.
In addition, the unique structure of the periscope lens cannot be matched with a larger aperture. The aperture starting from F/3.0 plus a smaller sensor will cause the imaging quality of the periscope lens to deteriorate in dark light. poor, so it is only suitable for capturing distant scenery in bright environments.
Take the vivo X60 Pro as an example. When this phone takes 5X zoom photos at night (or when the light is poor), it does not activate the periscope telephoto lens, but allows the main camera to take 5X zoom shots. Digital zoom, the imaging picture at this time is very blurry.
But when zoomed in to 10X, even in poor lighting conditions, the system will allow the periscope telephoto lens to perform hybrid zoom, and the image will be clearer than at 5X.
In fact, the photography logic of other brands is the same. By default, the periscope telephoto lens only works in an environment with good light, but after continuing to zoom, it will no longer be affected by the light.
What is the comparison of a periscope telephoto lens?
The physical structure of a periscope telephoto lens makes it difficult to match a CMOS sensor that is too large. Historically, it has only been used on the Samsung Galaxy S20. Ultra is equipped with a 48-megapixel sensor that may be a 1/2.0-inch outsole, but the newly launched Galaxy S21 Ultra has replaced it with a 10-megapixel sensor. It can be seen that the outsole and periscope structure The conflict is still difficult to resolve.
Therefore, at least in the short term, we should not expect that the periscope telephoto lens can achieve image quality comparable to the main camera, even compared with the main camera of mobile phones 3 years ago. For this reason, the development path available for periscope telephoto lenses is very simple, that is, see farther and shoot brighter.
Mobile phones represented by Huawei P40 Pro, Mate 40 Pro and Galaxy S21 Ultra increase the number of prisms in the periscope lens, allowing the light to be reflected multiple times in exchange for a 240mm focal length, which can achieve The ability to achieve an effective 10X optical zoom is twice that of a periscope lens with one set of prisms.
However, the periscope lens with this structure also comes at a price, which is that the lens aperture is further reduced to F4.9 and is more sensitive to ambient light.
In addition, multi-path reflection will also cause the problem of shaking more easily. It needs to be equipped with a more sensitive OIS anti-shake module to improve the user's shooting rate.
The road to popularization is long
From 2019 to now, periscope fixed-focus lenses have gone through two years, and the related industry chain is relatively mature.
In April 2020, Xiaomi launched the Xiaomi Mi 10 Youth Edition, which brought the periscope telephoto lens to the popular price of 2,000 yuan for the first time. It was originally thought that this would be an opportunity to popularize this type of lens, but now Today, periscope telephoto lenses are still the preserve of a few high-end flagships. For example, Xiaomi’s new Xiaomi Mi 11 Pro (starting at 4,499 yuan) and Xiaomi 11 Ultra (starting at 5,499 yuan) this year are not cheap. Redmi, which focuses on cost-effectiveness, has not yet picked up one. Taking over the mantle of periscope telephoto lenses.
Taking OPPO as an example, the previous generation Find X2 Pro also came standard with a periscope telephoto lens, but this year’s Find X3 Pro has been replaced with an ordinary 3X telephoto lens, and its long-distance shooting capabilities have been significantly reduced.
The only good news this year is that Motorola’s latest edge s pro is not only equipped with the Snapdragon 870 mobile platform, but also equipped with a 5X periscope telephoto lens. The starting price of 2,399 yuan is very sincere. .
I hope that in the future, smartphones will have fewer lenses (such as macro, depth of field, black and white) that are used to make up the numbers, allowing this more practical periscope telephoto lens to be used Come into thousands of homes.
The 5X periscope telephoto lens can usually achieve 50X digital zoom, while the 10X multi-reflection periscope telephoto lens supports 100X or even higher
The following are some of the periscope-equipped cameras Sensor specifications of mobile phone with telephoto lens:
Motorola edge s pro
Telephoto camera: 8-megapixel periscope telephoto lens
Equivalent focal length : 126mm
vivo X60 Pro
Telephoto camera: 8-megapixel periscope telephoto lens
Equivalent focal length: 135mm
Xiaomi 10 Ultra Commemorative Edition
Telephoto camera: 48-megapixel periscope telephoto lens
Equivalent focal length: 122mm
Xiaomi 11 Pro
Telephoto camera: 8-megapixel periscope telephoto lens
Equivalent focal length: 120mm
Xiaomi 11 Ultra
Telephoto camera: 48-megapixel periscope telephoto lens
Equivalent focal length: 120mm
Huawei Mate 40 Pro
Telephoto camera: 1200 Megapixel periscope telephoto lens
Equivalent focal length: 125mm
Huawei Mate 40 Pro
Telephoto lens: 8 megapixel multi-reflective periscope Telephoto lens
Equivalent focal length: 240mm
Samsung Galaxy S21 Ultra
Telephoto lens: 10-megapixel periscope telephoto lens
Equivalent focal length: 240mm