There are times when a filmmaker needs to record sound using a separate device from the camera, to record sound separately and then sync the sound to the video later, when editing. Usually, the reason for this is to increase the quality of the recorded sound because many cameras don’t record sound as well as external recorders can.
Another reason is so that the sound operator can move farther away from the camera and still monitor the sound being recorded. (Usually, of course, the sound operator has to be close to the camera in order to monitor the sound being recorded.)
When recording sound separately, you should try to make it as easy as possible to sync the picture and audio later in the editing tool. There are two basic ways to do this:
Use a clapperboard: A clapperboard is often used when making films to display information about the scene being shot — the scene number, take number, crew details, and so on. It’s also used to sync video and sound. When the clapperboard is snapped closed in front of the camera, it creates a visual cue on the video footage, whose sound creates an audio marker point that can be used to sync with the video when editing.
Record sound from both the camera and the external microphone: When recording sound on an external device, you may want to capture sound through the camera, too. This sound is a good reference, but isn’t used in the final edit. When recording sound through the camera you pick up dialogue, which can be used to sync the externally recorded sound to in the editing tool. This saves a huge amount of time trying to read people’s lips to sync the sound when editing.
When you record sound separately from the camera, you may consider using a device called a portable sound recorder. Portable sound recorders can be purchased from camera stores from around $100 to around $10,000. A good option is the Zoom H4N.
The Zoom H4N is an amazing little device that records great quality sound. It’s really portable and is a lot less expensive than most other portable sound recorders.
The great thing about portable sound recorders is that you can use them to record sound effects or voiceovers without having to set up your camera. You can use your portable sound recorder to record foley or wildtrack, which are background sounds that can be added to the film during editing. Foley or wildtrack sound fills out the sound in a scene and enhances the audience’s experience.
For example, if you are filming a party scene and you want to make it sound like there are loads of people at the party, you could film the scene with the actors you have and then record sounds of people talking and laughing and any other background noises from a real party you attend and then add these noises to the video when editing.