What is exposure?

Exposure in photography refers to the amount of light that is allowed to reach the camera’s sensor or film when taking a photograph. It is a critical element of photography that affects the overall look and feel of an image.

The exposure of a photograph is determined by three main factors: aperture, shutter speed, and ISO.

Aperture is the adjustable opening in the lens that controls the amount of light that enters the camera. It is expressed in f-stops, such as f/2.8 or f/8. A wider aperture, indicated by a lower f-stop number, allows more light to enter the camera and results in a brighter image. A narrower aperture, indicated by a higher f-stop number, allows less light to enter the camera and results in a darker image.

Shutter speed is the amount of time that the camera’s shutter is open when taking a photograph. It is expressed in fractions of a second, such as 1/250 or 1/60. A faster shutter speed, indicated by a lower fraction, allows less light to enter the camera and results in a darker image. A slower shutter speed, indicated by a higher fraction, allows more light to enter the camera and results in a brighter image.

ISO is a measure of the sensitivity of the camera’s sensor or film to light. It is expressed as a number, such as ISO 100 or ISO 3200. A lower ISO number indicates a lower sensitivity to light, while a higher ISO number indicates a higher sensitivity to light. Increasing the ISO can make the image brighter, but it can also introduce noise or graininess into the image.

By adjusting these three factors, photographers can control the exposure of their photographs and achieve the desired look and feel for their images.