What does ISO do on a Digital Camera?

ISO is one of the three pillars of photography along with aperture and shutter speed. It is a measure of the camera’s sensitivity to light, and it is an essential part of photography. The term ISO comes from the International Organization for Standardization, which is a standard-setting body that develops and promotes global standards. In photography, ISO is used to describe the sensitivity of a camera’s image sensor to light.

On a digital SLR camera, ISO is a setting that allows photographers to adjust the camera’s sensitivity to light. It is usually represented as a number, such as ISO 100, ISO 200, ISO 400, and so on. The higher the number, the more sensitive the camera is to light.

ISO is essential in low light situations where the camera needs to be more sensitive to light. In these situations, photographers often use higher ISO settings to capture more light and avoid using slower shutter speeds or larger apertures that can result in motion blur or shallow depth of field.

However, increasing the ISO setting comes with a tradeoff. Higher ISO settings can introduce more noise or grain into the image. This is because the camera’s sensor is amplifying the signal it receives to capture more light, which can also amplify the noise that is present in the signal.

Digital SLR cameras offer a wide range of ISO settings, which allow photographers to choose the best setting for the lighting conditions they are shooting in. For example, if shooting in bright daylight, a photographer might choose a lower ISO setting, such as ISO 100 or ISO 200, to avoid introducing noise into the image. Conversely, if shooting in low light conditions, a photographer might choose a higher ISO setting, such as ISO 800 or ISO 1600, to capture more light.

Some digital SLR cameras also offer an auto-ISO feature, which automatically adjusts the ISO setting based on the lighting conditions. This can be helpful in situations where the lighting conditions are changing quickly, such as during a sunset or when shooting indoors with artificial lighting.

In summary, ISO is an important setting on a digital SLR camera that allows photographers to adjust the camera’s sensitivity to light. It is a crucial part of photography, especially in low light situations, but photographers should be mindful of the tradeoff between higher ISO settings and increased noise in the image. By understanding how ISO works and how to use it effectively, photographers can capture better images in a wide range of lighting conditions.

Doug Marshall

Doug Marshall is a freelance photographer, photography instructor, professional blogger and pizza enthusiast. You can follow him (dougmphoto) on Facebook, Twitter and Instagram.