In filming Ah-Chung, Chang would often look for impromptu developments among the actors themselves. He would film them chatting and included bits of their discussions in the film itself.
拍《忠仔》時，張作驥常視演員的即興狀況發展，例如當演員以為彼此在聊天的時候，往往已經被攝影機拍下成為日後片段。