Tips For Variable Frame Rate Footage

We get a lot of calls from clients wanting to rent 'the camera that does variable frame rates for effects'.  After they've done some research, called all of their friends that have shot HD or variable frame rate, and come to us to get a quick 'once over' tutorial, they think their ready to go out and shoot.   Unfortunately, limited knowledge and lack of experience can prove disastrous in post.  To improve your chances for success as you enter variable frame rate world, we've put together a few tip that will definately help.
 
The first big issue that will simpify your life in post is not to mix differing frame rate footage on a single tape.  For example, if you record bars and tone at the front of the tape at 60p in the field, when you transfer the footage in post the playback VTR sees 60p at the beginning of the tape and assumes the rest of the footage on that reel is at the same frame rate.  If different frame rate footage is on that tape those scenes will have to be transferred separately, because the system reads a 5 second head/tail setting on the capture (or pre-roll) at only one the frame rate.  If the head/tail setting is set to 60p everything on the tape will be transferred at that rate.  Likewise, if you set the head/tail capture rate to 24p, the 60p footage on the reel will be captured at a 2.5 times larger frame rate.  The simplest fix for this is to record different frame rate scenes (4 to 60) on separate tapes (i.e. each different frame rate scene gets its own tape). 

Another option for those of you on a budget (i.e. who can't afford extra tape stock) is to group different frame rate scenes together on the tape.  This way when you get to post you can capture the footage in groups.  This approach is a little less elegant, but its way better than that having to transfer different frame rate footage scattered randomly on the reel.

To learn more about the intricacies of shooting on HD or other variable frame rate cameras, we recommend Goodman's Guide manuals.  They are well worth the investment if you are serious about shooting.