pinning drawings in space during a 3d camera move

I’m trying to create an animatic, using a 3d environment and 2d characters. Is there a way to do my camera move, then draw the characters to match the environment, and have the drawings pinned to 3d space? I’ve tried using an ortho lock, but then the drawings move with the camera. Otherwise, I don’t seem to be able to draw in the camera view after creating the camera animation.