What is the exposure rate in the camera?

Reciprocity rate, also known as reciprocity rate, is a term mostly used in film photography.

We know that there are two ways to control exposure, shutter speed and aperture. If two factors are changed at the same time, the exposure will be equal and the exposure result will be established.

The function of aperture and shutter is to control the amount of light. Camera lenses are marked with f/2.8, f/5.6, f/8, f/11, f/16, etc. This is the aperture coefficient. The larger the coefficient, the smaller the aperture; the smaller the coefficient, the larger the aperture. Shutter speed is the abbreviation of a fraction of a second, such as 125 for 1/125th of a second. If you reduce the aperture by one stop and increase the speed by one stop, the amount of light emitted onto the film will still be the same. This relationship between aperture and shutter speed is also called "reciprocity".

——The reciprocity rate refers to the density of the image generated when the photosensitive material is developed, which is directly proportional to the exposure duration and light intensity.