For many years, Mark Decker has practiced the art of photography. A highly popular activity among amateurs and professionals alike, photography allows an individual to capture an image of the real world and use it to tell a story. According to Decker, effective photography requires a well-developed command of fundamental concepts such as shutter speed, aperture, and film speed. While shutter speed and aperture play an important role in determining the amount of light that reaches the light sensor, film speed has a considerable impact on the quality of the image and the amount of film grain.

According to Mark Decker, film speed refers to the light sensitivity of the film or digital sensor, depending on the type of camera in question. Most modern color negative films and digital light sensors use a measurement system known as ISO, named for the International Organization for Standardization. As the film increases in ISO, it reacts more rapidly to incoming light and records an image on the lens more quickly. On the other hand, a lower ISO requires significantly more light to record an accurate image on either the film or digital light sensor.

Experienced photographers such as Mark Decker know that, while a high ISO setting has the ability to record images quickly and require little available light, they nevertheless sacrifice image quality as a result. Because the film or digital sensor has little time to record an accurate image, the resulting photograph typically contains a type of disturbance known as “grain,” which takes the form of randomly distributed dots across the image. Although many photographers have manipulated grain to produce certain effects in their artwork, most people regard the appearance of grain as unattractive.

Nearly all digital cameras feature a built-in light meter, which records the amount of light and adjusts the film settings. According to Mark Decker, light meters do not always produce the desired settings, as they may not adhere to the vision of the photographer. In a common example, a light meter will interpret a snowy landscape as exceedingly bright, causing it to darken the scene to the point that the snow looks almost gray. In scenes such as these, the photographer must often adjust the light settings himself.