Good question! Originally the Hi-Matic seal foam stopped right where the downward break began (at the film chamber). However, in some of the last models of this series, I've noticed they added foam all the way through that curve, so I think it is a matter of personal choice. I don't think you'd get a light leak there, but it might make you feel better. If you're using the 2mm pre-cut strips I sell, it is easy to just follow around the curve and be done with it.