Thanks for the input and opinions. I was thinking like orionid mentioned “as you can put a registration mark on a roll, shoot it up, rewind it, and shoot it again” except a digital equivalent. I had considered Kestrana’s concern “you have the option in your PS program to vet which of your images is used and which looks better on top or bottom, the amount of opacity used” and its why I solicited “any other stipulations”. It’s becoming clear that this would require more legislation which seems to contradict your apparent principles of keeping it as simple as possible, which I am in favor of.
The idea of leaving the shutter open will not likely work as the setup time between exposures would cause too much sensor noise, at least it does on my 20D, maybe my new toy (7d) would do better. Anyways, I guess I’ll just stay away from the idea for now.
