I'm shooting a video which is mostly VO. The actor is going to be on camera some of the time. Should we use the same mic for both. I was planning on using a Saken COS-11 for the on camera shoot. Should I use the Saken for the VO as well. I was thinking the audio would match better if used the same mic.
It sort of depends on if you "creatively" want to make it clear to the viewer that one is on location and 1 is added studio content. its a style thing, but if thats not part of the idea, then Eric is right, same mic in same location.
Of course, the best way to make two recordings match up is to do them during the same session with the same equipment.
Not clear on why the VO "must" be recorded ahead of the on-camera portion in some other location. Some details on why that's important might give people some clues to help you out.
But if you must record VO ahead of time, why not do both?
After your VO is recorded in your alternate location, just have your talent do the whole thing with one mic in your studio where the shoot occurs. At least you'll have that sound if your pre-recorded VO doesn't match like you want.
A distant second best is to use the same mic and settings (if possible) for both recordings.