What are the photographic elements?

The basic elements of photography are either color, light and shade or light.

Sensitivity: indicates the speed of photosensitive materials. Units are expressed in degrees or fixed. For example, "ISO 100/2 1" means a film with a fixed sensitivity of 100 degrees /2 1. The higher the sensitivity, the more sensitive the film is (that is, the less light is needed to shoot the same photo normally in the same shooting environment, that is, a higher shutter or a smaller aperture can be used).

Focal length: the distance from the center of the lens to the focal point. The unit of focal length is usually expressed in mm (millimeter). The focal length of the lens is usually marked in front of the lens, for example, f=50mm (this is what we usually call a "standard lens" because its viewing angle is the same as that of the human eye), and the focal length of 28-70mm (our most commonly used lens) is most suitable for taking portraits, 70-210 mm.

Shutter: A device used to control the exposure time. Shutters can generally be divided into curtain blinds, lens blinds and steel blinds. Among them, curtain blinds can be divided into vertical curtain blinds and horizontal curtain blinds. Steel shutter can reach higher speed (the highest shutter speed can reach112000 seconds or more at present). Generally, the highest speed of the inter-mirror blade shutter does not exceed 1/500 seconds, but the biggest advantage of the inter-mirror blade shutter is that the noise generated during shooting is extremely low, which is very conducive to sneak shots and can realize synchronous flashing within the full speed range.

Exposure: The process in which light reaches the surface of the film and makes the film sensitive. It should be noted that by exposure, we mean film exposure, which is a necessary process for us to obtain photos. Often depends on the combination of aperture and shutter, so there is the word exposure combination. For example, the shutter measured by the exposure meter is 1/30 seconds, and the aperture should be 5.6, so F5.6 and 1/30 seconds are an exposure combination.