What does the ISO in photography refer to?

ISO in photography refers to a scale for measuring film sensitivity to light. This measurement directly influences how sensitive a film or camera sensor is to light, which is crucial for achieving the correct exposure in varying lighting conditions. A higher ISO value indicates that the film or sensor is more sensitive to light, allowing for better performance in low-light situations, while a lower ISO is suitable for bright environments.

The significance of ISO extends to digital photography, where increasing the ISO can help capture images in challenging lighting conditions but may also introduce noise or graininess to the image. Therefore, understanding ISO is essential for photographers who wish to control and manipulate exposure effectively.