Filters and matte boxes do what you and the camera cannot. At a basic level, they work to reduce haze, glare or reflection in order to enhance images.
Attach filters directly to the front of the camera lens if you have a screw-on type, or place it into a matte box. Matte boxes are usually attached to a set of rods as part of a camera rig. These screw-on filters reduce atmospheric haze and protect that precious lens.
Look for thin filters that guard against fingerprints and dust. Clear filters stop liquids from hitting the lens. Be mindful, however that some filters cause reflections, flare and ghosting. Always test filters out before getting started to ensure they do not take away from the shot.
Some filters can evade reflections. The polarizer is one such filter and is a favorite for outdoor filming. Reflections are most common when filming near bodies of water. These filters can help the lens see below the water surface or peer through car windscreens.
Use a circular polarizer with an auto-focus and manual-focus lens, and rotate the filter to match the light direction.
To keep glare away and light at bay, use a matte box. These tools stop light from reaching the lens from all sides. A top flag blocks the sun or other light from above and adjustable side flags remove side spill.
Matte boxes contain stages for filter holders, which can be static and rotating, and hold square or rectangular filters. Extra stages allow operators to stack Natural Density (ND) filters to reduce light more by combining shielding levels.
Neutral Density filters come in solid or graduated versions. Choose ones with hard or soft edges. Solid ND filters come in grades of light reduction but do not change the color of light transmission.
Graduated ND filters on the other hand reduce light levels in only one part of the scene – usually the sky. These filters compensate for cameras that have a lack of dynamic range. Sky details that would normally be overexposed would be revealed.