80?? good luck haha thats a tall order. only tip i can give is get high up, like upstairs shooting down or bring a ladder. Only way you will see all their faces. Tuff part sometimes is getting everyone in same lighting. anyone in shadows will , with my luck, come out black.
10 people way easier if they stand on the stairs so u can get different heights for them. for come family i do her family, her side, his family, his side (boring), then i have all guys one side and girls other (boring too).
wow, id get nightmares thinking of shooting 80 guest at a wedding. almost none of them would even be looking at my camera unless i yell. good luck!!