How can ultra-wide-angle photos be almost distortion-free? Xiaomi Mi MIX 4 uses a 120° free-form surface ultra-wide-angle lens for the first time. By calculating the aberrations of each field of view on the holographic surface, each image point is corrected one by one to create a unique curvature of the lens, without algorithmic cutting, and almost distortion-free 120° super wide field of view photo. Today, Xiaomi mobile phone officially brought related science.
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The frequency of use of ultra-wide-angle lenses in mobile phone photography has gradually increased with the improvement of ultra-wide image quality. This is because ultra-wide-angle lenses can not only record more images, but also have advantages in picture composition that other lenses do not have. The ultra-wide-angle lens captures a more three-dimensional picture, and the layout of the front, middle and long-distance view can open up the space, highlighting the depth and layering of the picture, and the content is full but also more visually impactful.
However, traditional ultra-wide-angle lenses mostly use fixed-curvature rotationally symmetrical aspheric lenses, which can cause distortion problems of up to about 20%. For distortion correction, mobile phones usually adopt anti-distortion algorithms to achieve correction function by cropping the screen, but the problem that comes with it is that cropping will cause a part of the wide-angle viewing angle to be lost, making the picture shot by the ultra-wide-angle lens less shocking.
Mi MIX 4 uses another hardware-level anti-distortion method to achieve distortion-free ultra-wide-angle shooting: free-form surface ultra-wide-angle lenses. The free-form surface lens of Mi MIX 4 is more flexible. By calculating the aberration of each field of view of the holographic surface, each image point is corrected one by one, breaking the rotational symmetry, creating a unique curvature of the lens, without algorithmic cutting, almost straight out Distortion-free 120° super-wide field of view photos, realizing hardware-level anti-distortion, realizing the best image quality large image area super wide-angle imaging.
Why is it distorted
When shooting with an ultra-wide-angle lens, do you often encounter such problems? The left and right ends of the photographed buildings have barrel-shaped expansion distortion, which is like adding a haha filter to a straight building. This is the traditional ultra Wide-angle lens barrel distortion caused problems.
This is because the traditional ultra-wide-angle lens is designed symmetrically according to the central axis, and the curvature of any point is the same under the same radius, similar to an inflated football. The symmetrical design of the central axis will lead to optical aberrations generated by different fields of view when the light passes through the lens.
How free-form lenses make ultra-wide-angle lenses almost distortion-free
The optical surface of the free-form lens used in Mi MIX 4 is a combination of asymmetric, irregular, and complex free-form surfaces. It is more like a water-filled balloon. The curvature is continuously changing under the same radius, so it can be as long as possible. It can control the light aberration of different field of view and distribute the light intensity freely. It can even control the light incident angle, deflection direction and optical path difference through artificial design, thereby suppressing the distortion, and finally showing the edge distortion of only 1% In the photos on the left and right, the edges of the pictures almost appear “horizontal and vertical” to restore the real world.
The ultra-wide-angle lens of the Mi MIX 4 can not only achieve a wider viewing angle with hardware-level anti-distortion, but also has an excellent center image quality. After the super wide mode is enabled, in some scenes, the main camera and super wide will start shooting at the same time, and the two photos will be merged into one picture through SmartFusion technology. The angle of view in the center of the picture is about 85°, which is actually taken by a 100 million pixel main camera, while the edge is taken by an ultra-wide-angle lens. The super-high resolution of the main camera is added to the middle area of the ultra-wide angle, which greatly improves the image quality of the central area of the picture. Very suitable for shooting scenes such as large landscapes and buildings.
Extreme exploration is the most basic product definition of the Mi MIX series. On the basis of hardware, Mi MIX 4 pays more attention to the experience upgrade it may bring. In response to the long-standing ultra-wide-angle distortion problem, Xiaomi MIX 4 has achieved a perfect combination of distortion-free and good image quality by adding free-form lenses and super-wide-angle fusion Smart Fusion technology, allowing the ultra-wide-angle lens to have an experience comparable to that of the main camera.
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