The amount of light that reaches the film (or camera sensor). It determines how light or dark an image is. The exposure of an image is determined by the apertureThe aperture is basically a hole in the camera’s lens that lets light pass through it to the shutter and ultimately the film or censor. The aperture not only influences picture brightness but also regulates depth of focus. Most cameras are equipped with an iris aperture that can be freely adjusted or set according to pre-selected values. More, shutter speedThe time a camera sensor or film is exposed to light when taking a photo. More, and film speed (ISOInternational Organization for Standardization represents the film’s (or sensors) sensitivity to the light. The higher the number, the more information will be captured. 400 ISO film is more sensitive to light than 200 ISO film by 1 stop.).
During exposure, the sensors or chemicals on the film in analogue models, are subjected to the light outside the camera for a certain time.