Certified Professional Photographer (CPP) Practice Exam 2026 - Free CPP Practice Questions and Study Guide

A neutral density (ND) filter primarily serves the function of reducing the amount of light that enters the lens while maintaining color neutrality. This characteristic allows photographers to increase exposure without altering the colors in the scene. By decreasing the light hitting the sensor, photographers can use wider apertures or slower shutter speeds, enabling creative effects such as shallow depth of field or motion blur from moving subjects.

Using an ND filter effectively increases the exposure time required to achieve a correct exposure, which is essential in very bright lighting conditions, such as shooting outdoors on a sunny day. This capability allows for greater control over the camera settings and the artistic expression in the final image.

While achieving sharper images, altering color balance, and reducing motion blur are all important aspects of photography, they are not the primary functions of an ND filter. The main goal is to increase the exposure time necessary to obtain a well-exposed image under bright conditions.