Battlelog doesn’t offer a way to search for filming servers. Joining a Punkbuster/Fairfight enabled server is a great way to get your account banned if you use this program in it. Here are a list of approved servers you can use to join and film in.
VoteChange is a plugin that allows for players in the game to Vote for the next map. Some of the servers bellow have it installed. This will allow you to join one that is empty and change the map without having to contact the admins.
Blue Ent. Filming Server [EU]
View in Battlelog
[Vote for Map Installed]
Not Hattiwatti’s BFH Server [EU]