Neutral Density Filters (ND filters) are optical devices that reduce the intensity of light entering a camera lens without affecting the color of the light. They come in various strengths, measured in stops, allowing photographers to control exposure settings while maintaining the desired depth of field and motion blur. These filters are commonly used in photography and videography to achieve effects like long exposures in bright conditions or to create a shallow depth of field. By limiting light, ND filters enable creative control over images, making them essential tools for both amateur and professional photographers.