LOS ANGELES — Filmmaker Frank Darabont of "The Shawshank Redemption" fame has been dazzled by "The Shield" since it began in 2002. He finally took action — or more specifically, he shouted "Action!"

Invited by series creator Shawn Ryan to direct an episode of the dark, wrenching police drama, Darabont jumped in. His work on last night's episode, "Chasing Ghosts" (airs again at 7 p.m. tomorrow on Channel 554), cemented Darabont's admiration for TV in general and "The Shield" in particular.

"It starts with the writing," Darabont said. "I've never seen a show that takes the kind of chances this one does. It's swinging for the fences all the time, and there's not been one iota of slacking in the tension and quality of the stories they're telling."

No big-screen snobbery here. As Darabont sees it, "some of the best stuff is being done on TV these days."

But the reality is that television and film production are vastly different.

A series can't offer an impressive budget or the kind of leisurely, 120-day shoot Darabont enjoyed on "The Green Mile." An episode of "The Shield" usually gets about seven days of filming.

And instead of realizing a personal vision, as he did directing his Academy Award-nominated adaptation of Stephen King's novella for "Shawshank," he has a series template for tone and character to follow.

Darabont, making a rare foray into TV, was fine with it all during his work late last summer on the FX series. He's downright enthusiastic about the relative lack of control.

"Coming in and putting myself at the service of somebody else's creative vision is wild and liberating. ... This is play time for me. And working with a unit this talented, this cast and this script, wow, talk about a safety net."

"I love playing in their sandbox and not trying to turn it into my sandbox," he said.

On a sweltering Los Angeles day, with Darabont and the cast and crew camped out in front of an apartment building for a scene in "Chasing Ghosts," the filmmaker was clearly in charge but far from overbearing.

"I seem to recall that on those lines you were off the curb, but maybe I'm losing it," he counsels series star Michael Chiklis. "Where it lands naturally is better. Let's do it one more time. ... And action! Please!"

The episode is pivotal in the story line unfolding this season.

"The Shield" is immersed in the aftermath of police detective Curtis Lemansky's death and Strike Team leader Vic Mackey's (Chiklis) determined effort to find and destroy his killer — who viewers know is fellow lawman Shane Vendrell.

There was a deliberate effort to give Darabont a particularly juicy script, said Adam E. Fierro, who co-wrote it with creator and executive producer Ryan.

The hour "includes a huge emotional payoff, something that has been building since last season, and we held it specifically" for Darabont, Fierro said. "He's a great writer, and when you have a great writer reading your stuff you feel extra pressure."

Darabont slipped easily into the series' rapid-fire production rhythm, according to an admiring Chiklis.

"This is not a conventional shoot," Chiklis said. "It's really shot in a docudrama style — oftentimes, we don't even lay marks (for the actors). It's raw and ugly. We do it fast and furious."

The nine to 10 script pages covered in a single day of shooting on "The Shield" represent at least a week's production on a film, the actor said. Darabont embraced the rush.

"He's been passionate since the moment he walked on the set, like a 15-year-old kid at a rock concert," Chiklis said. "He's been on fire the whole time. ... He's moved faster than anybody else. He's so definitive. He knows exactly what he wants."

Besides directing the pilot for the new Jeff Goldblum series "Raines," Darabont's TV experience includes a 1990 cable TV movie, "Buried Alive," and scripts for George Lucas' "The Young Indiana Jones Chronicles."

The first two features he wrote and directed, 1994's "Shawshank" and 1999's "The Green Mile" received Oscar best-picture nods. He knows what he wants to pursue artistically — "good, character-driven stuff" — but worries about whether it's possible.

"Truth is, it's getting harder and harder in my line to get movies made. The studios are getting so ..." he searches for a word, then settles on "blockbusterish," a reference to big-budget movies that play it safe.