Problem with ratio

We ran into a problem regarding the editing process on the video. Due to the ratio of the stop motion stills the moving images are the same ratio so we need to find a way to fix this so the the things we record fit with the rest of the things that we have. We have yet to find a way to do this in Premier Pro to fix the problem. We are working on ways around this such as using the shots to appear and play parallel with each other.