If you want to keep it simple, I believe Canon offers software that makes your DSLR look like a webcam to your computer. You just have to connect it with a USB cable, run the software, and it will look like a really high quality webcam to applications. Then you can just record video from your "webcam" together with audio from your microphone directly, avoiding the steps of importing audio and video separately and syncing them later. (I've done this on Windows, but I don't know if it's supported on Mac) Another approach would be to plug your lapel mic into the DSLR and record audio and video together on the camera.
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