A film that opens with the wholesome vision of a disc jockey interviewing the Lone Ranger and ends with a dead man spilling blood all over his hotel room has a long way to go for the viewer to believe his protagonist could change so much. But Greg Kinnear’s depiction of Hogan’s Heroes star Bob Crane goes practically nowhere.

In “”Auto Focus,”” based on the book “”The Murder of Bob Crane”” by Robert Graysmith, Kinnear (“”As Good as it Gets,”” “”Loser””) teams up with Willem Dafoe (“”Spider-Man,”” “”Shadow of the Vampire””), who plays Crane’s best friend and eventual murderer. With a cast like this, I anticipated greatness.

I was impressed by Dafoe’s depiction of his character, John Carpenter, whose latent homosexual urges toward Crane and his symbolic obsession with a technological age that will inevitably leave him behind propel his pathetic and stagnant lifestyle toward killing his best friend. I was honestly given the creeps.

But Dafoe’s stellar ability was not mirrored by Kinnear, who is the type of actor that does not soar when stretched beyond his bounds. His character makes sudden leaps from a sober, wholesome family man to an orgiastic party freak, to a burnt-out, tired old man without any sense of transition or indication where he might go next. Rather than bringing us down with him, we get left behind, shaking our heads in disgust.

As for director Paul Schrader (“”American Gigolo””), he did what he could with a fundamentally unsound premise. The story of a man whose career only saw success for six years and who was then bludgeoned to death with a tripod is not necessarily one I would call filmworthy. However, Schrader’s direction keeps the film afloat — if only just barely. The camera work mirrors the emotional state of the characters; the occasional dream sequence/mental freakout gave us insight into how out of control our hero really was. The film’s varying range of lighting techniques keeps the visuals fresh.

In a movie where you know the main character is going to get killed, the last thing you want is to find yourself waiting for that to happen. I was anticipating it about half an hour before it actually came. And when it did come, it was out of the blue.

This film was not all bad. I didn’t walk out on it. But considering the talent behind it — in both acting and directing — it fell short of its potential.

Auto Focus

***

Starring Greg Kinnear and Willem Dafoe.

Directed by Paul Schrader

In theaters Oct. 25

Rated R