Blocking, Secondary defender does not establish legal position

This is an example of a defensive foul for blocking against a player who is in the act of shooting.
The defender here does NOT establish his position before the offensive player started his upward motion, and thus, this is a defensive foul. The defender here needed to establish himself in the path of the offensive player before the contact was made, and also BEFORE the offensive player starts his upward motion. Since the defender failed to do this, the contact here is illegal, and it is a defensive foul for blocking.