What is the main function of shutter speed in photography?

The main function of shutter speed in photography is to control the amount of exposure time. Shutter speed refers to the duration for which the camera's shutter remains open when capturing an image. A longer shutter speed allows more light to hit the sensor, which is particularly useful in low-light conditions or when needing to create motion blur for artistic effect. Conversely, a faster shutter speed reduces exposure time, freezing motion and preventing the image from being overexposed.

This essential aspect of photography directly influences the brightness of the image and can be used creatively to convey motion, such as capturing a fast-moving subject sharply or creating a sense of movement through blurring. Understanding and manipulating shutter speed is critical for photographers to achieve the desired visual effects and control over their images.

The other choices relate to different aspects of photography. Adjusting the lens focus pertains to how sharply the subject appears, modifying ISO settings involves changing the camera's sensitivity to light, and determining the aperture size is about adjusting the size of the lens opening to control light and depth of field. Each of these factors plays a role in exposure and image creation, but they do not specifically refer to the duration of exposure, which is the primary role of shutter speed.