The brilliant Dr. Gary Miller, became a Muslim in 1978 - Adul Ahad Umar. He is a Canadian mathematician. In one of his speeches he mentions that he would not appear before the camera to preach Islam but does not give the reason for it.
He must be very old now. Is he?
You may hear Dr. Miller's speech on "Amazing Qur'an" at:
http://www.mydeviant.com/miller/gary_miller.html (Many speeches)