Happy I found this little nugget when I was scattering trees on the doodle from the other day. You can turn on and leave on the camera frustum in Houdini. Frustum is a fancy way of saying field of view or to dumb it down more, what the camera can see.
RMB click on the camera and click on “Frustum Handle“ (Or click F). Then RMB Camera again and hit the check box, “Persistent”.