I remember being told years ago that you should leave all camera movements to the director and not include them in the script. I.e. a CU of a person's face screaming just turns into "so and so screams".
Since I was told this, I've always avoided entering any camera directions (pans, CUs, Crane shots etc.) This can affect the joke, though. For instance, I have scenes in the script I'm writing at the moment where the joke depends on cinematography/editing as much as it depends on dialogue and action.
I've realised that others often put camera directions in scripts so I'm sure it's ok for me to do so, but I was wondering whether anyone feels there are any rules around this - should camera directions only be included in scripts when absolutely essential and avoided as much as possible?