

what am i doing wrong?
I've been shooting on my nikon EM 35mm film camera on fujifilm 400 iso. a lot of my photos keep turning out grainy like this even though i've set the camera's iso to 400 and i change the aperture with every photo.
my initial thought is maybe my perception is off with how much light i should be letting in dependent on the environment? like maybe i should start assuming that the picture will ALWAYS turn out darker?
i don't THINK its the camera because some pics do turn out good. help!!!