The focal length of the lens: d, also known as the number of millimeters of the lens, refers to the distance from the center of the lens to the focal point of the light when the parallel light incident.
The focal length of the lens determines the size of the image, the Field Of View (FOV), the depth of field and the perspective of the picture.
Whether you really understand the physics or not, just remember that the smaller the focal length, the wider the Field of view(FOV), the larger the range of field, and the smaller the object in the picture;On the contrary, the larger the focal length, the narrower the Field of view(FOV), the smaller the range of view, and the larger the object presented in the picture.
1080p video resolution is 1920*1080, 1920 times 1080 is equal to 2,073,600: about 2 million pixels
HDMI transmission distance is generally up to 15 meters
When the color of the light emitted by the light source is the same as the color of the light radiated by the absolute black body at a certain temperature, this temperature of the absolute black body is called the color temperature of the light source
