What is the purpose of a neutral density filter?

The purpose of a neutral density filter is to limit the amount of light entering the lens without affecting the color of the image. This allows photographers to use longer exposure times or wider apertures in bright conditions. By reducing the light, a neutral density filter enables creative effects such as motion blur in moving subjects, softening of water in landscapes, or achieving a shallow depth of field in bright sunlight.

This tool is especially valuable in high-contrast situations where traditional settings could lead to overexposed highlights. The effectiveness of such a filter lies in its ability to provide greater control over exposure settings, thus enabling more artistic freedom in various lighting conditions.