i find the camera doesn't reduce my enjoyment of the race, just changes how you're watching it, but having friends does. that sounds rude. and also a bit sad. but i'm kind of used to getting really absorbed in the races. with friends there it's quite hard!
(also: cameras are fun but they're really heavy if you're carrying reasonable glass. so mine comes out relatively little at le mans, and my toy dslr comes to play instead
)