Faith and reason are not spheres of influence that overlap, they are completely separate. Faith is defined as knowledge ‘verified’ by faith. The definition is circular. Faith is belief without reason. Faith is by definition, irrational (knowledge lacking reason). Faith claims knowledge of the unknowable; it is contradictory. The fact that it is irrational does not make it inherently unethical or bad. It is what it is, it is irrational. Faith in god is not a type of knowledge; it is belief without reason. Religious faith is a conventional abstraction.
Faith is different from belief as well. Belief is a statement or idea of pre-knowledge or pre-understanding that can be verified and tested using the scientific method. A belief can be proven true or false. Newton believed gravity existed before he could fully define it or state it into a hypothesis.
Faith is irrational belief. Belief that cannot be tested.