The convenience of having neutral density and color-balancing filters installed within the body of a video camera cannot be overstated. But despite being available at all times, easy to change and almost impossible to scratch or otherwise foul, the internal filters selected by the camera manufacturer provide little more than the means for achieving accurate exposure and color balance.
For creative control of the image, videographers must learn to rely on filters attached in front of the lens. A quick check of manufacturers' Web sites Tiffen and B&W reveals a dizzying array of filters for everything from controlling flare, glare and focus to allowing flattering close-ups and creating a film-like look by taking the hard edge off the video image. To make selecting filters even more of a challenge, all are generally available in various sized rectangles for use in a matte box, circles to insert in a lens hood retaining ring, and threaded to mount directly to almost any size lens.
While the best way to get started is to obtain a set of diffusion filters on demo or from a rental house so you can make your own comparisons, two filters which belong in almost any optical accessories kit are the polarizer and a general purpose diffusion filter such as Tiffen's Black Diffusion FX. The polarizing filter will give you deeper blue skies in your outdoor shots, and will eliminate glare and reflections from windows or when shooting objects under glass. A diffusion filter--and there are many to choose from--can smooth facial blemishes without making a noticeable impact if you stick to the lower numbered grades. Start with a grade 2 and see how it looks on your camera.
