Advanced Video Production Techniques

So you've figured out how to shoot some video and managed to load it into your computer. It looks good, but something's not quite right. The video just isn't quite as bright and colorful as you remember. That's because there are fundamental differences between televisions and computer monitors.

Before we dive into the technical minutiae of display technologies, let's talk briefly about some simple tools you can use to improve your video image before it hits tape. Lens filters can be a very cost-effective way of improving your video quality.

Understanding Lens Filters

Many of you may have at one time or another played around with photography. If you ever progressed beyond "point-and-shoot" cameras, one of the first accessories you probably purchased was an ultraviolet (UV) filter for your lens. UV filters are useful because they prevent UV light from entering your lens, which can make your pictures look slightly blurry, and because they protect your lens. Mistakenly scratching a $25 filter is far preferable to scratching a fancy zoom lens that cost you hundreds of dollars.

The same applies for your DV camera. Protecting your investment by buying a cheap and replaceable filter is a good idea, and as with photography, filtering out UV light gives you a cleaner video image. If you're wondering how a UV filter works, chances are good that you've experienced it many times. Every time you put on a pair of sunglasses, you're filtering out UV light (among other things). The immediate effect is a clearer, crisper image. Even though we can't see UV light, it interferes with our ability to perceive visible light. DV cameras have the same problem, so a UV filter is always a good idea.

A number of other lens filters can be used to improve the quality of your podcast. The next few sections discuss them generally. To learn more about exactly which filter you should use with your model of camera, you should consult online discussion boards and digital video camera review sites.

Diffusion
Diffusion filters soften your video image. We've all seen diffusion at work in the movies, particularly in the film noir genre. The camera cuts to a shot of the gorgeous female actress, and she's practically luminous. This is achieved using a fairly heavy diffusion filter. Although this would be overkill for most podcasting applications, using a light diffusion filter gives your podcast a distinctive look. It also can help your encoding quality.

Many DV cameras default to shooting a very high contrast image, and some even use special processing to exaggerate the edges between objects. This can be okay in situations where there isn't much contrast to begin with, but if your scene is lit properly, you should have plenty of contrast. Video that has too much contrast looks amateurish. Using a diffusion filter can mitigate this by softening the entire image ever so slightly. Diffusion filters can make your podcast look more "filmlike," which is generally desirable.

Video with too much contrast also is more difficult to encode, because it has lots of extra detail in the frame. This makes the encoder's job harder, because it tries to maintain as much detail as possible. Using a diffusion filter helps soften the image slightly, which reduces the amount of detail, thereby making the image easier to encode.

Color correction
The UV filter described at the beginning of this section is essentially a color filter, designed to filter out colors beyond our range of vision. There are many more color filters that you can buy for other situations. One of the most useful for many podcasters is the fluorescent light filter. Fluorescent lights emit a very particular type of light, with a lot of extra green in it. Because of the large amount of green content, fluorescent lights tend to make people look slightly ill. Using a fluorescent filter when filming in offices or other fluorescent lighting situations can make your podcasts look warmer and more natural.

You also can buy filters that are designed to enhance certain parts of the color spectrum. These are fairly specialized and not for the average podcast producer. If you're looking for a special effect, you're probably better off trying things out in your video-editing platform, where you can safely undo those mistakes.

Polarization
Polarization filters are used to filter out reflected light. For example, filming through a window can be very difficult because of the reflections. Using a polarization filter removes this reflected light and allows you to film what's on the other side of the glass. Similarly, if you're trying to film under water, for example fish in a pond, you need a polarization filter. Polarization is often used in sunglasses for this reason.