How to Shoot Great Video With a DSLR
The Next Level: Capturing Better Audio
Types of External Microphones
One of the first things I learned in filmmaking was that you can have a good film with a bad picture, but you can never have a good film with bad audio. Alas, one common feature of all DSLRs is terrible built-in audio recording. No camera I have used has handled audio in a competent way.
Most of the time, a camera provides only a small jack input that records heavily compressed mono sound. The audio on all cameras is pretty bad for the most part, so if you intend to capture good audio at all, you need to invest in a microphone (or a few).
You'll find three main types of microphones.
Lapel mics (lavalieres): These can be wired or wireless. They're great when you have one person as a focus point; you just mic them up and let them speak. I use wireless mics, as they give me much more flexibility in moving around the subject.
Shotgun mics: These are directional microphones (they pick up audio only in the direction you point them). They're another good choice for single-subject shots, but for footage in which you want to pick up environmental background noise while still covering the subject.
Omnidirectional mics: These general-atmosphere microphones cover a large field of sound. They can be brilliant for capturing the sound in an event where you have no key speaker.
Here are the main points to consider when looking for a microphone.
1. Will you plug it straight into your DSLR?
If you intend to do so, you'll need a powered mic. Make sure to have the appropriate adapters for plugging it into your camera.
2. Will your filming environment be windy or have external noise?
If so, look for a mic with a wind sock. Several third-party suppliers have great wind socks and other effective sound-dampening tools.
3. Do your research and listen to sample audio tests.
Much like lenses, microphones can be very expensive at the top end--and they're equally important for achieving professional-level results. And as with lenses, you won't find a one-mic-fits-all solution; so many options are available, however, that you're sure to encounter something that works for you. Online forums and review sites have a lot of good information about new mics, and you can even listen to sample tests of audio quality online.
External Audio Systems
For recording great audio, I personally prefer a two-system approach, meaning that I have a totally separate setup for audio capture in addition to my camera setup. This arrangement allows much more flexibility in terms of controlling the audio. Most cameras have no independent controls for audio--and if they do, they're buried in the menus.
I use a system that attaches to the top of my camera, which helps me keep the camera and the audio system together when I'm traveling around. You'll find many separate audio products on the market, as well as converter boxes that let you plug XLR leads into them and power the mics you use; this is called "phantom power."
One thing to keep in mind here is how long the battery will last if you are using phantom power. I quickly found out that although in theory it's great to plug two or more phantom mics into your system, that setup drains the system's battery quickly.
It's best to look for a converter box that sends a signal to override the automatic gain in the camera. That makes editing footage much easier, as you don't have to resync all your audio.