If ever a film event crystallized a particular moment in U.S. culture, it was the San Francisco Intl. Film Festival in 1968, where establishment squares and counterculture icons jockeyed for the limelight.On the one hand, Gene Kelly, Lillian Gish, Edward G. Robinson, Rita Hayworth, Bing Crosby and John Huston held court as guests, along with burgeoning “Funny Girl” superstar Barbra Streisand. Even executive director Claude Jarman, the Oscar-winning former child star of “The Yearling,” hailed from showbiz royalty. On the other, there were incendiary new films by Godard, Cassavetes and Melvin van Peebles. The Beatles’ psychedelic “Yellow Submarine” lured delighted “heads” to a special midnight launch, while Andy Warhol’s “Lonesome Cowboys” attracted FBI agents sniffing out rumored pornographic content. Perhaps most exciting of all was the first appearance before a U.S. audience of Michaelangelo Antonioni, whose “Il Grido” hailed a new cinematic voice to American cineastes hungry for art films at San Francisco’s own inaugural edition in 1957. More recently, Antonioni’s “Blowup” — both existential murder mystery and mod snapshot of swinging ’60s London — had made him an international cause celebre. Antonioni was in California to film “Zabriskie Point,” the director’s oblique take on the youth protest movement in this country. As if on cue, just three days prior to the Italian maestro’s fest appearance, students across the Bay had barricaded themselves inside a UC Berkeley building, protesting the cancellation of a course taught by Black Panthers leader Eldridge Cleaver. Saying “the San Francisco audience” was “the only one I would face in person” in the U.S., Antonioni was received by a full house of hippies and undergrads with, according to Variety at the time, “a reverence usually reserved for visits of high-ranking Vatican prelates.” Under the headline “This Year It’s Really a Swingfest,” S.F. Chronicle critic Stanley Eichelbaum opined: “I cannot remember when a festival has tried to cover more bases, or made more effort to stimulate young people (by) playing up new directors and controversial, with-it themes.” Then-program director Albert Johnson hailed ’68 as “the year of revolution.” There had even been fears that general protests and strikes might cancel the event. Jarman now calls the period “a very volatile time (in the Bay Area) but also a fascinating one. There was always some pushing and shoving at the festival itself between our society (attendees) and the real film buffs. To me, that was a very healthy situation.” This balancing act between glamour, politics and the cutting edge of cinematic art has always characterized SFIFF, which this year celebrates its 50th anniversary as the Western Hemisphere’s oldest extant film festival. “The hippies proved to be just as excited about movie stars as everyone else,” harrumphed the L.A. Times in ’68. Yet now, as then, the core SFIFF audience is, in current exec director Graham Leggat’s words, “very thoughtful, independent-minded and adventurous,” with a genuine “hunger” for unknown, even difficult works. A second-generation local theater owner, Irving M. “Bud” Levin, founded the festival in 1957 out of a conviction that his native city “needed to keep its place in the arts world with an international film festival celebrating (movies) as an art form.” The ambitious 14-day debut included films from 12 countries, among them work from emerging masters Kurosawa, Visconti, Wadja and Satyajit Ray. Back then, the volunteer-run affair was so homey that parties and guest receptions were held in Levin’s own home. It didn’t take long for SFIFF to expand, professionalize and gain a major media profile. Initial reluctance from Hollywood itself to support this unaffiliated event to the north gradually thawed — especially once Johnson began hosting tributes to “golden age” screen legends in 1965. Memorable moments included Bette Davis’ 1969 confession that her “greatest disappointment in later life” was not playing Martha in “Who’s Afraid of Virginia Woolf?”; and Sam Peckinpah’s tipsy but polite 1974 defense of his violent oeuvre. Producer Tom Luddy, participant in various capacities between the late ’60s and early ’80s, says the tributes featured at Telluride, which he co-founded in 1974, were “completely taken from the template Albert put down. There was no other festival that made tributes and retrospectives so important.” When Peter Scarlet signed on in 1984 for a long stretch as program director, he dug even deeper into emerging international talents, from premiering low-budget first features by then-unknowns Spike Lee and Christopher Nolan to showcasing Malaysian cinema. “I think Peter Scarlet established that this is a place where there’s an audience for films from very remote places,” opines S.F.-based film critic-historian David Thomson, adding that in this respect the fest also “suits the city as a natural response to its ‘United Nations’ of a great many small ethnic-national communities.” Leggat’s regime promises to uphold that explorative legacy while adding new-technology elements and heightened collaborations with the Bay Area’s filmmaking/exhibiting communities. There will, of course, still be the occasional spritz of an A-list celebrity landing, or what he calls “the straw that stirs the drink.” But upon reaching what board member Fred Levin calls “the second half of its first century,” SFIFF remains committed to emphasizing art over flash amid a global festival scene more crowded and competitive than Levin’s late, fest-founding father could have imagined.