I’ve been shooting video with a DSLR for a little over a year now. It’s great to have the type of control that DSLRs are famous for without the price tag and weight of a ENG camcorder. The form factor isn’t perfect. I wish my T3i could shoot longer shots. I wish I had a dollar for every time someone asked, “Wait, are you shooting still pictures or video?” None of those things are the that big of a deal though.
What is a big deal is audio. I don’t know if every DSLR has such horrible microphone preamps, but Canons certainly do. Everything recorded on the camera, whether through the built-in or an external microphone just sounds bad. The frequency response is okay, but the noise floor is too high. Said another way, there is a fairly loud hiss that’s recorded at the same time as the good audio.
There are three ways to fix this problem. You can either fix it in your audio editing software, record audio on a separate device syncing it during editing, or replace the mic preamps.
1) Fixing it with your audio software.
I’ve tried to fix audio recorded by my T3i more than once. Each time, I found the results less than satisfying. You’ve got a few options, of course. You can try applying a gate but that doesn’t really affect the hiss while there’s recorded audio that’s louder than the gate is set to trigger.
You can try using some audio cleaning function Audacity, Sound Soap, or Audition all have. It’s really easy to overdo this. When you do, the resulting audio sounds mechanical.
You can try using a graphic equalizer to pull the frequency of the hiss down relative to the other frequencies, but I’ve never gotten it quite right without making the other audio sound bad — either too tinny or too muddy.
I’ve even resorted to adding a music bed. This kind of works, but you’ve got to be careful not to drown out the spoken word. A soft-spoken person might not be audible at all once you bring the music bed up to mask the hiss. It also means you always have audio in the background whether you want it or not.
2) Recording audio separately.
Until recently, I believed that this was the best option. You needed to carry a separate recorder. You needed to make sure that the recorder had adequate battery supply and enough room on its recording media to get the audio that you want when you want it.
You also need a way to sync the audio. Film traditionally did this with a clapboard. At the beginning of a scene, someone would hold the clapboard where all the cameras could see it. Then the person would clap the hinged piece of wood on top. This would provide a visual point at which an audio cue could be synced.
For movies, this was perfect. For documentary purposes, this was a problem. Every time you’d start and stop recording, you’d have to clap the slate again. Imagine the problem of doing this during a wedding or any other live event.
You can also sync with software. PluralEyes is the industry standard for this, but Final Cut Pro X also does it. The problem is that you need audio on your video file for this to work at all and once in a while software will make a mistake forcing you to line up the audio by hand.
3) Replacing the preamps.
While I’m not against voiding warranties, this doesn’t require any alteration of your camera’s hardware. If you lower the gain on your camera to the lowest point, one notch above off, you can feed a line-level signal into the mic input.
I was initially interested in doing this when I saw a video from JuicedLink showing how their low noise preamps could do this. Unfortunately, I spent most of my budget on the camera, so I didn’t have another $300-400 to add a preamp, although I really wanted one.
On one of the videography forums I frequent, someone suggested that a small headphone amp might do the trick. I ordered one, but while it helped, it wasn’t as useful as I’d hoped.
About this time I noticed that we had an old Zoom H4 digital recorder at church. I borrowed it and found that the line out worked well for this purpose. The problem is that it wasn’t mine and it had a short that prevented it from running off batteries. That’s fine for my home studio, but less than ideal for the field.
Last week, I found the best solution so far. Since smart phones are such popular devices for doing just about everything, you can get an iPhone mic preamp with phantom power for about $35-40 (called the iRig mic preamp). Deejay at DSLRFilmNoob.com figured this one out. You’ll need a quad mini to two stereo mini jack adapter unless you want to do hack the iRig pre (and void its warranty).
For strained budgets, using the iRig pre might be the best choice and you can use either a dynamic or condenser mic, too. I’m about to buy one myself. I love it when you can get what you need for less money.
How have you tried to get good audio with a DSLR?