Zac Efron had jitters shooting a sex scene with Heather Graham in their film, “At Any Price.” “I’ve been a fan of Heather’s and had a crush on her since I can remember,” Efron sheepishly said at a Cinema Society and Bally-sponsored screening. “She’s always been the epitome of that perfect girl. I wanted to get it right.” Graham added, “Zac and [director Ramin Bahrani] were like, ‘We’ve never done a sex scene before . . . We’re kind of nervous.’ I thought it was so funny. I was suddenly this expert.”