In "No Small Affair," Charles Cummings (Jon Cryer) is an alienated teen-age shutterbug who uses his camera to shield him from the world; his life changes when he photographs Laura (Demi Moore), a rock singer trying to break into the big time. "You're terrific," he says to her. "No, you're terrific," she says to him.

Guess again.

"No Small Affair" is a good example of the revised teen sex movie, which centers on a Morose Young Man unimpressed by the wild life swirling around him -- he'll take romance. But even the facile crudeness of a movie like "Porky's" seems to have demanded too much of screenwriters Charles Bolt and Terence Mulcahy; the masturbation jokes, dirty puns and bared breasts are added almost as an afterthought. In what must be somebody's idea of synergy, the "I wanna be a star" genre is stitched on, in the character of Laura, who belts out half a dozen songs which, thanks to the miracle of modern marketing, are now available on Atlantic records.

Why Moore was cast in this role mystifies, since she doesn't sing at all -- she lip-syncs, in a tortured style that has less to do with "Heartbreak Hotel" than the heartbreak of psoriasis. As she croaks throatily, pointed nose and jaw jutting beneath her frazzled hair, you think you're watching Boy George transported to "Macbeth": "Eye of newt and toe of frog, Wool of bat and tongue of dog . . ."

Cryer does a creditable impersonation of Matthew Broderick -- the nasal monotone, the cheese-eating wince. But with lines like these (watching porn on TV, he waggishly remarks, "I think this is the climactic scene"), it's hard to tell whether he can do anything more.

Then again, "No Small Affair" is a good-looking movie, with the lush, thick artistry of cinematographer Vilmos Zsigmond. Now he's really terrific.

"No Small Affair," opening today at area theaters, is rated R. It contains nudity, profanity and sexual themes.