Film director Lee Chang-dong ended his 16-month stint as South Korea’s culture minister Wednesday to return to filmmaking.Lee, who won helming honors at the 2002 Venice film fest for “Oasis,” was a surprise pick to join the cabinet of President Roh Moo-hyun. The film industry gained a powerful ally in government, as Lee had been an active advocate of the quota system that requires theaters to devote 40% of screens to local pics. He will be replaced by career politician Chung Dong-chea. The change comes at a tense time, as the film industry is gearing up for a fight with the government, which wants to cut the quota. It has long been a target of U.S. trade pressure.