What Is ISO on a Digital?

An ISO setting on a digital camera refers to the light sensitivity of the camera's sensor. The ISO levels of digital cameras are defined by the International Organization for Standardization in specification ISO 12232:1998. Before digital cameras were invented, ISO referred to the light sensitivity of film.

Features

Higher ISO settings are more sensitive to light, making it possible to take pictures in low-lit settings. However, increasing the ISO setting also degrades the quality of the picture, usually making it grainy or adding "noise."

Levels

A normal ISO level is 100. Some digital cameras always use an ISO of 100, but other cameras allow you to change the level or automatically adjust the level depending on the available lighting.

Benefits

For best results, use the lowest ISO level possible. However, increasing the ISO level can help you take better pictures, especially in dark settings such as churches, ceremonies or indoor sporting events. Increasing the ISO level can also work well in locations that don't allow flash photography.

References

• Duke University: Digital Photography FAQ
• Digital Photography School: ISO Settings in Digital Photography
• Fullerton College: Understanding Exposure