The complete riddle of word guessing: the correlation of O (word guessing in calligraphy and painting photography)

O(a-type calligraphy and painting) Answer: aperture

Aperture is a device used to control the amount of light entering the photosensitive surface of the fuselage through the lens. Usually in the camera. We use the f value to represent the aperture size.

For the manufactured lens, we can't change the diameter of the lens at will, but we can control the luminous flux of the lens by adding a polygon or circular aperture grating with variable area inside the lens. This device is called an aperture.