I once read an article at my friends house about some photography equipment but I don't remember the name of it. Here is what I remember of it: - It allowed to increase the shutter speed up to 30 minutes (even longer if desired) - Some photographer used it in the night and the picture showed the path that the stars took. - It held the lenses open (and didnt let them close) up to the point where you choose to close them. Anyone knows what I am talking about?? Help would be greatly appreciated.