Remove the filter and the light wave range taken by the mobile phone camera.

After the infrared filter is removed, it needs to be replaced with coated white glass with the same thickness and size, otherwise it will change the refractive optical path and lead to incorrect imaging.

The range of light waves shot by the mobile phone camera is 380nm-780nm, which is basically the wavelength range of visible light. Both the filter and the camera CD itself are sensitive to infrared light, but when the CD senses infrared light, the focus will shift and the color will be cast. Therefore, the CD of ordinary color camera should be affixed with a filter/film to filter out infrared light, and the image will be normal. Double filter is actually a filter (thick, optical glass)+filter film (thin), which can be switched automatically.