If the focal length of the lens is less than the normal visual angle of human eyes, the periphery of the image will expand outward after imaging, which is the optical deformation of the lens; This is inevitable, because when shooting with a mobile phone, people's arms are limited in length and close to their faces. When designing camera lenses, manufacturers must design wide-angle lenses with short focal length, so that more people and suitable backgrounds can enter the imaging range, so they will be deformed.

Even professional photographic equipment, taking portraits with exaggerated wide-angle lenses will cause deformation. Some technologies are good and can be controlled in optical design, while others are ordinary, and the distortion will be corrected by software. Therefore, the focal length of the lens used to shoot portraits with professional equipment is exquisite. The 85mm lens is most suitable for shooting portraits without barrel distortion, which makes people look beautiful. The general mobile phone camera is a lens with an equivalent focal length of 35mm, which is bound to be distorted. Some have designed an equivalent focal length of 28mm in order to shoot a wider landscape, which is even more exaggerated. If you shoot at close range, it will definitely be distorted.

Solution-post-software adjustment distortion;

Another way is: now there is a selfie stand, put the mobile phone on it and then stay away from the head, so that the imaged face will not be too deformed.