Another question from a reader:
I’m just deciding whether to get a Canon 7D, and have what may be a stupid question: if you use a Zoom recorder, does it get synched while you are shooting, or do you have to do that afterward? Thanks! Absolutely LOVE this site.
The short answer is that you sync it the audio from the Zoom with the video from your camera in post-production. But there’s more to it than that.
Timecode
Professional production equipment uses timecode to label each frame on each device recording sound and video. Production crews often distribute timecode (TC) and a sync signal around the set. The sync signal keeps all equipment marching to the same beat and the TC gets recorded on all cameras and audio recorders. When you get to post it’s easy to make every shot and every audio file lay on the timeline in sync.
DSLR cameras do not have timecode, neither does the Zoom. And neither has an input for accepting the genlock sync code. These devices run “wild” and that can be an issue when you get to post.
The most basic thing you’re going to need is a way to sync the audio from the Zoom with the video from the DSLR.
Clap Sync
The simplest (and cheapest) solution is to clap your hands in front of the camera at the start of every take to create a visible and audible sync point. It’s pretty easy to match the visual point of contact with the spike on the audio track.
If you are shooting a more complex piece it’s worth getting a slate. You get the same sharp contact to match with a spike on the audio track plus you have reference info written on the slate to use when logging the clip for editing.
Working from a script with a shot list and using a slate to mark takes is more work but it pays off all the way through the production. Plus you’ll look more like a real film crew!
Sync in Final Cut
If you’re using Final Cut Pro here’s a trick that makes it easy to adjust the audio track in very small increments.
Sometimes after lining up the audio and video using the visual cues you’ll find there’s a slight delay sound between the camera reference audio and the high quality audio from your recorder.
You can shift either of these tracks in one frame increments by holding down the command key (apple key) while you click and drag the clip. Final Cut will scale the mouse movement down and provide a + or – sign along with the frames you’re moving. You should be able to slide the clip one frame forward or backward and get a perfect sync.
PluralEyes
If you have lots of clips to sync you’ll be glad to know about PluralEyes, a software tool that will analyze the audio track on the video clips and in your audio files and match everything up for you.
I use both methods. If I have just a few clips it’s easy to do them by hand. If I’ve got a lot of clips, PluralEyes is a smarter choice.
Here’s another tip for processing lots of audio clips.
Just like grading the video for the best look, you’ll want to process the audio for the best sound. If you’ve only got a few clips and the audio is in pretty good shape you can use the audio tools built into Final Cut.
Take one clip and work on it to get the levels where you want them. Then bring in an EQ filter and get the sound where you want it. You may need to correct the levels after you’ve equalized the audio. You may want to add some dynamic level processing to “fatten up” the sound or to take care of a problem in the track.
When you’ve got everything the way you want, select the clip in your timeline and copy it. Then select all other clips recorded with the same setup (same mic, room, recorder, talent, etc.) and right click (control-click) and choose Paste Attributes.
Choose the audio attributes you want to transfer and click OK. All the filters and settings will be applied to all the clips. If needed, you can work on any clip individually to refine the filter settings as needed.
If you have a tip or trick for syncing sound, please leave a comment. And let me know if you have questions about syncing sound or other production issues with DSLR cameras.
-a-
Awesome write-up. Very helpful! Thanks.
What about if you use the line out signal from the Zoom into the camera’s mic input, won’t that make it stay in sync? Or do you lose any quality doing this vs. using the recording from the Zoom itself?
Actually, that’s a very good practice. If you are using a shotgun mic on a boom or a wireless lav on the talent you’ll be recording sound close to the source. Your camera can be several feet away which can create a tiny bit of delay between the two sound files.
Pro audio guys send a feed from their mixer to the camera just so the cam sound has the best quality and it’s a backup for their recording.
But none of this makes any difference to syncing up the tracks in post or keeping them in sync. The tracks are still free running with no time code so you’ll have to sync them up on the timeline.
In the old days we used to record timecode to one of the audio tracks when we had a free running recorder. That made it super easy to find clips and sync up in post.
You can still do that but you’ll need a time code generator and a wiring setup to distribute the signal to the camera and your recorder.
If your project is that advanced you’ll already have a pro sound guy taking care of all of this for you!
Thanks for the question, I hope this makes things clearer.
-a-