Compact upright camcorders like my trusty old DCR-PC5 are great if you want something that's portable and ideal for candid shots, but they're not without their drawbacks. As well as being notoriously uncomfortable for long periods of handheld shooting, they generally have internal microphones in the strangest of places, usually somewhere between the viewfinder and the lens. This doesn't mean that they don't work; but you'll find that this increases the chance that the audio coming from your subject will be overridden by coughs, sniffs and mutterings coming from you. Horizontal camcorders fare slightly better, as they typically have front-facing microphones beneath the lens barrel, but to get the best results you'll need an external microphone.
Of course, there's no guarantee that your camcorder even supports external microphones, as many compact or entry-level models lack the necessary line input or accessory shoe. If this includes yours, consider your wrist slapped for not choosing your model more carefully.
Omni mane padme hum
Regardless of the type of external microphone you choose, you'll find that the immediate benefit is a reduction in the amount of unwanted camera noise on your soundtrack caused by the whirring and humming of internal components.
But don't just rush out to your local electronics outlet to buy the first thing the sales geek points at. Getting the right kind of microphone depends upon the task you have in mind, and there are some basics you need to know first.
There are three main types of microphone; omni-directional, directional (cardioid) and shotgun (hyper- or super-cardioid). These descriptions refer to the microphone "pattern" or area of sensitivity - see screen shot. In case you were wondering, cardioid microphones are named after their heart-shaped sensitivity patterns (from the Greek kardia).
So, if you're looking for a camera-mounted microphone that isolates forward audio from any ambient around the camera, then a hyper-cardioid microphone like the one in this picturewould be a good choice. Bear in mind that these are not "long distance" microphones, they simply pick up forward audio more readily than surrounding audio. All environments have a "Critical Distance" at which the ambient noise has the same intensity as the subject noise, and even a shotgun microphone won't help at that point.
Ordinary cardioid microphones are better in shoots where you need to pick up a degree of surrounding noise, or for instances where you don't want to lose volume if the subject turns their head or shifts - like interviews or performances. Because the sensitivity pattern isn't as tight as a hyper-cardioid, regular cardioid microphones are best placed closer to the subject, either on a tripod, a table-mount, or a boom.
Finally, omni microphones are the best choice for instances where you want to record the whole soundscape. Although this means that they're not great for isolating the subject audio from the surroundings, they're less susceptible to "pops" on the recording caused by "plosive" speech close to the pickup (words beginning with P, B, T, etc) which makes them ideal as lapel (lavalier) microphones. You can get cardioid lavaliers, but I usually go with an omni for this role as they're largely unaffected by head movements. Because they're very close to the audio source, you can usually depend on the Inverse Square Law to isolate the subject from the surroundings (see "It's the law").
TIP: Unless you have a high-end camcorder with XLR inputs - which can carry power - you'll find that most of the external microphones need batteries to work. So double-check that they're switched on and charged before shooting. I did a wedding once where I had to rely on the internal pickup from my roaming shots because I'd forgotten to switch on the main camera's microphone. Needless to say, it didn't go down well.
Finally, if you're going to be working outside, consider a windjammer or shield for your microphone. Onboard pickups are usually covered by a wire mesh, which only makes matters worse when the wind picks up. Fitting a windjammer to your microphone (see here) will help to cut down on wind noise. Alternatively, look in your camcorder's setup to see if it has a "wind cut" feature. This will cut down on the amount of low-frequency noise that gets onto your recordings. It may give your audio a slightly muffled sound, however, so try it for size before you go using it in an important shot.
Next time I'll be showing you some of the techniques that can be used to help sweeten up your audio recordings.
It's the law
Just like gravity, light and radiation, sound is subject to a little rule known as the Inverse Square Law, which states that quantity is inversely proportional to the square of the distance from a point. Which probably doesn't help explain things much. I could start banging on about spherical wavefronts, dissipation and particle velocity, but all you need to know is that sound intensity decreases rapidly as you move away from the source.
Double the distance between the microphone and the subject, and the sound intensity will drop by three quarters, as shown by the graph left.
The saga continues
Last month, you might remember that I showed you how to use Premiere Elements and Photoshop Elements to create a lightsaber effect in your own movies. If you tried it for yourself, you'll know that it really is a labour of love.
In my quest for "The Perfect Lightsaber Effect", I've played with a variety of programs; After Effects, Photoshop, Media Studio Pro, even the now-defunct Commotion Pro, all of which have one thing in common - they cost a lot of money.
If you were hoping to spend your cash on props for your fan film, rather than rotoscoping software, you might be interested to know about LSMaker, which is absolutely free, and on this month's cover disc. It's a little unpredictable, it's poorly documented, and it doesn't deal with obstructions/overlaps very well, but it's actually a lot faster than conventional rotoscoping techniques, and ideal if you can't afford a high-end compositor.
Not only that, but LSMaker's creator, Viktor Kovacs, has also produced a program to give you the Star Wars opening crawl title, and a tool for adding audio effects in real time (also on the cover disc). For more information, check out the Web site at http://lsmaker.uw.hu/page.php.