what i use is the strap that came with the summit climber. it has a prussic knot on a rope that goes around the tree so you can slide it up or down to get it out of the way
if you have to turn to the side and it would get in the way of the shot. you could tie your own if you want here is how http://www.animatedknots.com/prusik/index.php?LogoImage=LogoGrog.jpg&Website=www.a nimatedknots.com