What can I do if I was videotaped without my consent?

Well if it was something that could be seen from outside the property then they can do so.

Unfortunately, there really is nothing you can do. There is no law that requires your consent before you are videotaped in your backyard. However, depending on the circumstances, there may be an issue regarding an invasion of privacy. Specifically, if your backyard is "private" in the sense of having a privacy fence, dense shrubbery, etc., then perhaps your privacy was invaded if your neighbors had to go to some effort to tape you. If you were plainly visible to your neighbors, that is a different story.