Whether it’s a music video, Hollywood blockbuster or 30-second television ad, nearly all of the images presented to grab our attention are altered in some way. While many are manipulated during post production, adjustments that set the visual tone of a scene are very often achieved with the creative use of lens filters.
Though filters are helpful to all videographers, and literally hundreds of options exist, it’s easiest to decide which type will best assist you by first determining what you’ll use them for.
If you describe yourself as a "grab-and-go" shooter, whose camcorder is ready to record spur-of-the-moment events, then you may choose practical problem-solving filters. However, if you fall under the "video artiste" category, taking time and effort to craft each frame’s composition, lighting and style, you’ll likely obtain filters for specialized image enhancing capabilities.
Let’s start with the former group of videographers. If you are a grab-and-go shooter, you will want to select filters for color correction, glare reduction and lens protection. Check out the following common-use filters:
Clear filters really have just one purpose: to protect expensive lenses from damage that can be caused by unpredictable conditions encountered on location. A damaged filter is obviously much cheaper to replace than a lens. Protection from things like inclement weather, ocean spray, sand or dust can be reason enough to include a clear filter in your camera bag. Simply remove and wash the filter that has become smudged or fogged, something that’s not quite so easy with the camcorder lens. If a filter gets scratched, pitted or hopelessly dirty, just throw it away and get a new one. They are relatively inexpensive and easy to procure.
News photographers, the ultimate grab-and-go shooters, often put an ultraviolet filter (known also as a skylight, or simply a UV filter) over their camera lenses to combat harsh outdoor light while providing protection from the elements. In this case, lens protection is a bonus, as the UV filter’s main objective is to screen out ultraviolet light. UV filters slightly enhance image color, contrast and reduce haze in distant scenes. Many videographers keep an ultraviolet filter permanently mounted on their lens.
Most of us are familiar with the effect that polarized sunglasses have on reducing reflections and glare. Unlike sunglasses, the effect of professional polarizing filters can be continuously varied and, as a result, go much further in their effect. Like the glasses, these filters reduce reflections and glare. But they can also darken a sky while leaving the clouds just as white as before. Polarizing filters also reduce the effect of underwater light refraction and make it easier to see fish and natural surroundings. Polarizing filters also remove the glare from windows, making it easier for your camcorder to shoot through the glass. Polarizing filters need to be oriented by rotating the filter in front of the lens to achieve the best results. Once you have found the optimum angle for your polarizing filter it may be wise to make a visible mark on the rim so you can position it the same way to match the setting on another day of shooting.
Graduated Neutral Density Filters
Occasionally it’s desirable to reduce the contrast ratio of a shot. A graduated neutral density filter can be used to dim the powerful light of a bright sky, for instance, while allowing the full intensity of a subject’s shadowed face to enter the lens. Using the correct graduated filter, you should be able to retain both the flesh tones in the face and the clouds in the sky.
Filters for the Video Artiste
For the more visually-inclined videographers out there who want to dabble with light and color much the way a painter mixes his oils, special effect filters offer a whole palette of choices for designing an image’s through-the-lens look.
You know those scenes in which "fingers of light" project out from the sides of shiny objects and bright lights? Star filters make them possible. Their effect, while hardly noticeable in normally lit scenes, comes to life in dark shots that contain bright lights, especially sharp points of light. A star filter is basically a piece of glass with a microscopic grid of crossing parallel lines cut into its surface. Star filters can produce four-, five-, six- or eight-point stars, depending on the lines engraved on the surface of the star filter.
An offshoot of the star filter is the starburst filter, which adds color to the diverging rays. Be aware that both star filters and starburst filters slightly reduce the overall sharpness of the image, which may or may not be desirable.
Diffusion and Fog Filters
Diffusion and fog filters are two of the most popular special effects filters. To soften the look of a shot or to mitigate wrinkles on your talent’s face a diffusion filter can be just the thing. These filters soften harsh lines without making the image appear fuzzy.
Suppose you need to suggest a foggy morning. A fog filter creates the effect when nature doesn’t come through and without the extra budget needed for a fog machine.
Both diffusion and fog filters come in varying degrees of intensity so you can fine-tune the effect you want to convey. A makeshift diffusion or fog filter can be made by stretching a piece of sheer nylon stocking over the lens.
Colored filters let you paint your shots as you shoot. For example, in a scene that takes place on Mars, you may decide to simulate the Martian atmosphere by placing a green filter over the camera lens. Make sure that you white balance your camera before placing the colored filter over the lens, or the white balance system will try to cancel out the effect of the green filter. A gradient filter will let you create a beautifully colored sunset even at midday.
Whether you want to protect your camcorder’s lens, reduce reflection and glare, diffuse someone’s wrinkles or paint your shots with color, lens filters are relatively inexpensive tools that are well worth looking into.