This is not "Stand Your Ground": It's not his ground, and he was asked to leave it, therefore he was trespassing.
c) A person who has a right to be present at the location where the deadly force is used, who has not provoked the person against whom the deadly force is used, and who is not engaged in criminal activity at the time the deadly force is used is not required to retreat before using deadly force as described by this section.
As I understand the SYG concept, you may SYG wherever you have a legal right to be. He failed that standard.
He also failed the "has not provoked" standard, in that walking onto somebody's property with a video camera, and refusing to leave, is a provocation in my book.....
Murder. Possibly premeditated/malice aforethought.