Clearing Up The Noise Part I: Shortfalls In Capturing DSLR Audio

Photographers develop a sense of visual acuity after years of experience; thoughtful composition, artistic light placement and an intimate knowledge of camera settings come only with practice. Sound engineers are no less particular when it comes to honing their craft, and all professional filmmakers know the importance of capturing high-quality sound. As Scott Diussa, Field Operations Manager for Nikon, states in his blog post, “If [the audio] doesn’t sound good, then people won’t pay attention to the awesome images and video you put together. These three pieces, photography, video and audio need to be treated as equals.”

Modern DSLR cameras are fantastic for recording brilliant, crisp, HD video. They are not fantastic for recording sound. This is true for five main reasons: most HDSLRs (as of March 2011) employ consumer-grade automatic gain control (AGC), they don't capture great sound in the first place, they pick up sounds from the camera such as image stabilization and focus adjustments, they don't have XLR inputs, and sound can't be monitored when recording.

 1. Automatic Gain Control

Piano Concert: AGC flattens the dynamic range of music at a concert, rendering the audio uninteresting and unusable.Piano Concert: AGC flattens the dynamic range of music at a concert, rendering the audio uninteresting and unusable.AGC may not be a problem if you are filming your kids in your living room, but for most filmmakers creating video for an audience, it is something that needs to be overcome. Auto gain works to level out sound irregularities by boosting quiet audio and diminishing loud audio. This poses problem when there are periods of silence, as it boosts unwanted ambient noise. As with focusing, strive to gain as much control over your craft as possible; you wouldn't want to rely on autofocus when an actor steps onto the set, and you shouldn't rely on AGC to choose what sound to include when you're interviewing someone on location.

2. Poor Internal Microphone Quality

Internal microphone Canon 5D Mark II: The internal microphone on the 5D Mark II (red circle) is unimpressive at bestInternal microphone Canon 5D Mark II: The internal microphone on the 5D Mark II (red circle) is unimpressive at bestIn addition to employing AGC (which can't be turned off on most DSLRs today), the camera's internal mic can't be expected to meet your recording needs for the same reason a kit lens can't be used for sports photography: different situations require different solutions. Even if their was a one size fits all mic, the internal mic isn't high quality even for the most basic occasions.




3. Unwanted Noise

Because the microphone is internal, it picks up the smallest sounds from the camera. Adjusting focus, focal length, and even the lens's image stabilizing adjustments will be picked up by the internal mic.

4. No XLR Connections

XLR Cables: XLR cables are common on professional microphonesXLR Cables: XLR cables are common on professional microphonesHigh quality sound can be lost on its way from a microphone to the recording device; this is why professional cameras have XLR connectors built-in. Professional microphones can be plugged in directly to the camera – a feature lacking in DSLR cameras.


5. Can't Monitor Sound

Headphones: A pair of good headphones is essential for monitoring audioHeadphones: A pair of good headphones is essential for monitoring audioDSLRs today also provide no way of monitoring sound, so noises that you might not even think of can ruin your audio – the breeze that picks up on an outdoor shoot or the air conditioner that kicks on won't be detected until everyone has packed up and gone home if you can't monitor the audio in real time.

While these shortfalls may seem significant, they can be overcome. In Part II: The Solutions, I cover a range of solutions employed by professionals and hobbyists for capturing usable sound.


Mar 10, 2011
by Anonymous

In many professional film

In many professional film making operations, it's most desirable to use a separate audio recorder anyway.

With all the wireless and wired mic's that can litter a film set, you're also going to want a decent mixer in between those and your recorder. You'll also probably want a good EQ too. Ideally, you want a complete multi-track recording setup on set, so you can easily correct individual actor's voices later.

For hobby film-makers; consider investing in a Marantz or other high-quality audio recorder and a couple of wireless lapel mics and receivers. Most musical instrument shops will carry this kind of stuff as it's common stage equipment. Use a cheap mixer and you can record 4-12 mics at once or just use the left and right channels on your recorder for a two mic setup. A clapboard used before and after a take helps you sync the audio to the video later.