Hi,
Hans said it right. It is all about cooperation but I personally feel that a director should know the principles and choice of lenses, sound recording and even technique of lightings. He may not have to learn them formally but he should gain the knowleges from the DOP during off-shooting time. Otherwise it would cost the production time quite a some. With this knowledge, a director can exploit the equipments to give a better impact on the visual to effectively pass his message in the film. David Sweetman sounds it rightly in the beginning of his reply. I fully support him. In fact, I have been trying to pass this thought to many potential directors as I find many living directors still ignorant about these.