The beauty of photographic filters is their two-fold (sometimes more) function.
- To protect the surface of your lens against dust, moisture and the occasional thumb print
- To improve the quality of the pictures you take
Your results will depend on the kind of filter you use. So here is a very brief list of common filters and their uses.
- UV / Haze filters protect the surface of your lens against scratches, dust, moisture and fingerprints, which in the long term cares for the coatings on the front element. These filters also minimize atmospheric haze, which results in better overall image quality.
- Polarizing filters reduce or eliminate distracting reflections from the surface of glass, water and other polished surfaces, darken skies, make clouds pop from their surroundings and saturate color by reducing glare.
- Neutral density or ND filters block out light from reaching the sensor (or film) to shoot at wider apertures under bright lighting conditions, blur moving objects in the frame and allow for better exposure control when shooting video or film. These filters block out varying degrees of light to suit your desired result depending on the lighting conditions.
- ND Graduated filters darken or tint the top or bottom (or left and right) part of the frame while leaving the opposite side untouched. They are useful for exposing for scenes with extreme lighting differences on the top or bottom. Reverse graduated filters are also available. These darken the scene from the centre outward and useful for where the light is bright at the horizon or near the centre of the frame.
A note about price: The difference between an inexpensive filter and one that requires more investment has to do with the quality of the glass (the costlier filter most likely contains optically better glass), the quality of the coatings and the thickness of the ring (better filters have slimmer rings to prevent vignetting). Square and rectangular filters like these made by Lee and Benro are more versatile, but they do require holders and extra care when handling.