What does shutter speed refer to in photography?

Shutter speed is defined as the duration that the camera's shutter remains open, allowing light to reach the camera's sensor (or film). This measurement is crucial in photography as it directly affects the exposure of the image and the way motion is captured.

A faster shutter speed can freeze motion, making it suitable for action shots, while a slower shutter speed can create a sense of motion through blur, which can be artistically desirable in some contexts. Therefore, understanding shutter speed enables photographers to manipulate light exposure and motion effects in their images more effectively.

The other options address different aspects of photography—such as light intensity, lens characteristics, and image clarity—that do not pertain directly to the concept of shutter speed itself.