While it’s true that most of the on-board microphones on HD DSLRs provide stereo sound (excepting a few that are monaural), their utility is limited by their fixed position on the camera. They also lack control over incoming audio and have a tendency to pick up the inner workings of the camera and the lens as part of the video’s sound.
The best way to avoid these technical shortfalls is to use external microphones. Though a few of the current video-capable DSLRs offer gain control, which boosts or reduces the level of sound coming in—some even include an automatic gain that can override the delicate audio being captured in some situations with superfluous noise—external microphones typically give you much more sophisticated options for working with incoming sound and volume. With an external mic, audio is much cleaner, and it’s also more likely to be free of the ambient noise of the camera since audio is coming from an external source designed to pick up sound from a specific area.
Thankfully, there are a variety of solutions that meet the specific needs of HD DSLRs, and here we look at a few of the most basic and common mic configurations. A few words of advice when making a selection: Check to make sure that your camera has a stereo input before purchasing a mic; not all of them do. Also be aware that longer onboard mics can protrude into the angle of view of a lens when using wide-angles, especially with fisheyes lenses.
The PRO 24-CM camcorder microphone from Audio-Technica includes paired cardioid elements in a basic X-Y configuration, which is angled at around 90º to each other for ideally capturing stereo sound in a two-mic setup. The PRO 24-CM mounts to the hot-shoe of the camera. It’s fairly lightweight at 3.9 ounces and includes a removable windscreen. Estimated Street Price: $69.
Perfect for portability, the Azden SMX-10 is built to be compact at a weight of just under 2 ounces and a length of 7 inches. There’s a lo-cut switch for reducing ambient wind noise, and the mic is powered with a single AAA battery. It includes a windscreen and hot-shoe mount. Estimated Street Price: $65.
Built to be compact at 6 inches and light-weight at 3 ounces, the Røde VideoMic Pro shotgun mic is an on-camera stereo mic that attaches directly to the hot-shoe or to boompoles. Powered by a 9V battery, the mic features a foam windshield, a two-step high-pass filter for reducing ambient noise, a three-position level control for setting gain and a shock mount for isolating the mic from vibrations that could affect sound. Estimated Street Price: $229.
Sennheiser is a popular name in audio, and its MKE 400 compact shotgun is a mic that reduces side noise and includes settable sensitivity for long or short distances. A single AAA battery provides up to 300 hours of operation, and a foam windshield and shock-mount are included. Estimated Street Price: $199.
TYPES OF MICS
There are highly specific microphones available for any variety of sound situations, but for photographers who are only recently getting used to working with audio, basic on-camera mics will keep your system compact and portable while still making your audio much better.
In general, microphones are classified by the directional characteristics in which they capture sound. Mics that respond to sound in all directions are considered to be omnidirectional, while unidirectional mics are particularly sensitive to sound from a single source.
Shotgun. Shotgun mics are extremely unidirectional. They utilize specific directional pickup of audio to cut out the background noise while honing in on the source. They often employ screens to cut down on the ambient sound of wind, and they can be held outside of the frame by a boom to get as close as possible to the audio source or talent. The closer your mic is, the cleaner the audio will be. Better directional mics even will allow you to adjust the internal components for distance control.
Cardioid. You’ll hear the term “cardioid” a lot, as well as related names like “subcardioid,” “supercardioid” and “hypercardioid.” Cardioid refers to the heart-shaped pattern of sound waves captured by these types of microphones, which places an emphasis on the sound directly in front of the mics. Peripheral audio is recorded from the sides, as well, and in the case of sub-, super- and hypercardioid, sound is captured from behind the mic, to a lesser extent. Cardioid mics are the most common type of directional microphone, especially for interviews, newscasts and events.
Lavalier. Lavalier mics (also called lapel mics) are popular when sound is coming from a fixed source, in newscasts or talk shows, for instance. Lavaliers are attached to the clothes of talent via a clip, and they can be wired or feature a wireless system with a short broadcast range. The advantage is that sound is captured from a very close source, often only inches from the speaker’s mouth. The disadvantages are that they limit the talent’s mobility, and good wireless systems also involve a transmitter and a receiver, which can be complicated to work with until you learn the system. There can be interference with wireless systems, too.
Camera companies also offer their own proprietary mics for their systems. Sony‘s ECM-CG1 compact stereo microphone, for instance, is incredibly stealthy at only
1.9 ounces and a length of just under 3 inches. It matches the aesthetics of Sony’s compatible Alpha series of DSLRs, currently including eight video-capable models. List Price: $149