The candidate for attorney general badly needs exposure in Southern California, so the other day he held a press conference right in front of his opponent's Los Angeles office.

But as the reporters gathered around and the lone TV camera switched on, everything went wrong.

"I've asked . . ." shouted Arlo Smith over the traffic on Temple Street.

Suddenly, no words would come out.

"Uh, excuse me," he said finally after a mighty clearing of his throat.

"I've asked Ira Reiner, district attorney of San Francisco. . . ."

Whoops, wrong county.

Reiner is the district attorney of Los Angeles County.

Smith, in fact, is the district attorney of San Francisco County. And as he tries to get the Democratic nomination for attorney general, reality has set in.

Not only does Reiner avoid gaffes when the TV cameras are rolling, he has an enormous advantage in the attorney general's race because of years of media exposure in Southern California, where most of the state's votes are.

A California Poll last October found that Reiner was known by 55% of all registered Democrats; Smith was known by only 17%.

Still, Smith keeps hammering away, and he can point to some pluses.

Both the National Organization for Women and the main police union in the state, the Police Officers' Research Assn., have endorsed him. It is the kind of left-right support Smith got when he came from nowhere to beat the incumbent district attorney 11 years ago in San Francisco.

These days Smith spends most of his weekends meeting with Democratic activists and potential contributors in Southern California. And to show how serious he is, Smith, who has personal family wealth, recently put $500,000 of his own money into the campaign.

In addition to a solid record as San Francisco district attorney, he can argue that he would make a good attorney general because he was a deputy in that office for 20 years.

But he knows he is going to have to shout to get attention.

"Mr. Reiner should stand up and take responsibility for his actions," Smith yelled the other day across from Reiner's office on Temple Street.

Three buses roared by and nearly drowned him out.

Smith blasted away at Reiner for the recent revelations that some jailhouse informants used by Reiner's staff concocted or twisted the information they gave to the prosecutors.