Which type of camera filter is used to reduce the amount of light entering the camera?

The ND (Neutral Density) filter is specifically designed to reduce the amount of light entering the camera without affecting the color of the image. This is particularly useful in situations where the lighting is very bright, as it allows for longer exposure times or wider apertures than would otherwise be possible, enabling creative effects like motion blur in fast-moving subjects or achieving a shallow depth of field in bright environments.

By blocking a certain amount of light, ND filters help in controlling the exposure level and providing more flexibility in settings where you might want to shoot at a wider aperture for a blurred background, or at slower shutter speeds to create motion effects. They are essential tools for videographers and photographers working in varying light conditions, especially for outdoor scenes.

Other types of filters serve different purposes: polarizing filters reduce reflections and enhance colors, UV filters primarily protect the lens from dust and scratches (with minimal effect on the image), while infrared filters are used for capturing infrared light, which is entirely different from regulating general light levels. This distinct functionality of ND filters makes them invaluable in the realm of video production.