Suppose you render a cube, that you have translated with glTranslatef(0,0,-5); What is your view vector in that case?
What i thought, because you are looking from (0,0,0) to (0,0,-5). The view vector would be Endpoint - begpoint : (0,0,-5) - (0,0,0) = (0,0,-5) and after normalizing (0,0,-1).