When entrepreneur Irving “Bud” Levin started the San Francisco International Film Festival in 1957, his intention was to compete with the prestigious festivals already thriving in Berlin, Cannes, Edinburgh and Venice and to establish the U.S. as a viable member of the international film-festival circuit. Today, as its 50th anniversary edition begins (the event runs through May 10), it’s clear that America’s oldest film festival, which features 25 juried awards and is presented by the San Francisco Film Society, has established a venerable presence on the North American circuit — even though it might not necessarily have eclipsed, say, the Sundance Film Festival just yet.