One thing i have noticed about FO:NV is that the draw distance of npc's and enemies is not far away enough. i can get an enemy in vats and have only a small part of the enemy show up visable on the screen.

i pre ordered the game so i got the binoculars, and the strangely short draw distance makes them about as useless as icewater in Alaska.

if your on console I dont think you can on pc its the npc slider I think.

In the game launcher under settings -> advanced, I believe it's the "actor fade" slider