Magic Lantern Forum

Using Magic Lantern => Hardware and Accessories => Topic started by: IndyP on August 08, 2012, 06:22:59 AM

Title: External Recorder Audio to Camera
Post by: IndyP on August 08, 2012, 06:22:59 AM
Hi Everyone,
    I’ve just purchased a Tascam DR100 MK11 and Tascam gives the following information on how to hook the DR100 up to a DSLR camera:

    (The separate line out and headphone out on the DR100 allows you to listen in headphones  while you send a copy of the signal to your camera to sync up later).

    When recording audio with an external recorder using and external microphone, why would  I also need to send a copy of it to the camera when the camera itself is recording the audio which can be used to sync up later? Unless the “signal” they mention is different to the “audio” which I mention, but I’ve assumed they are one and the same thing. Am I missing something here?
Title: Re: External Recorder Audio to Camera
Post by: Led on August 08, 2012, 10:03:45 AM
Hi, there a few reasons you might want to feed into the camera, the most common one being you can't be bothered syncing the sound later.
You could use the in built mics on the Tascam which are not only better than the camera mic, but are also stereo, and you'd get a better sounding stereo audio track on the video in camera. Because the Tascam has xlr inputs with 48 volt phantom power, you could also use better quality condenser microphones, and get an even better stereo (or mono if you choose) audio track, and still record it onto the video, so later on you don't have to resync the external recording.
Even if you are using the external recording and resyncing it later, having exactly the same audio on both the recorder and camera means later on when you zoom in on the waveform to match sync, the waveforms will be exactly the same to look at, whereas if you use the camera mic they will look a little different even though it's the same sound.
The other thing that can make it a little trickier with syncing later is how far the camera is from the audio source. Sound travels at roughly 1 foot per millisecond (not exactly, but easiest rounding of number to remember) so if you have a boom or lav mic right by the actor, but the camera is 15 feet away, the camera mic will pick up the sound 15 milliseconds later than the boom/lav. So when you sync to the camera mic, you can be slightly out. 15 milliseconds maybe some people wouldn't notice, but 1 frame at 24 fps is about 41 milliseconds, so if there's 20 feet between the boom and the camera you are talking half a frame out.

Still none of this means you cant just record to the Tascam and sync to the camera later, it just makes things easier.
Title: Re: External Recorder Audio to Camera
Post by: IndyP on August 08, 2012, 05:51:51 PM
   Just prior to reading your post, I began to think about a couple of the points you mention. The first was that capturing the same audio on both the camera and the recorder would allow more efficient synching up later. And the second was that you could use the DR100 much in the same way you would use a Juicelink or Beachtech for better preamps to feed good audio into the camera.

   This, along with the other points you mention have given me a few more ideas on how I can use the DR100.
  Thanks a lot Led.
Title: Re: External Recorder Audio to Camera
Post by: Malcolm Debono on August 08, 2012, 07:46:33 PM
Led posted some pretty good points. One other point that isn't mentioned is recording from an XLR mic straight to camera, which is very handy if the mic requires phantom power.