That is not a problem for the movie industry, which rents the camera systems for short periods. (Other companies, including Gyron Systems International, Tyler Camera Systems and Spacecam Systems, also offer stabilized motion picture cameras.) But the need for maintenance made the systems largely impractical for full-time use by police, the military and television stations.
After Mr. Chamberlain led a management buyout in 1987 of the engineering company that had come to control the Wescam technology, he turned its attention to introducing a technology that was more robust.
Instead of providing stability, its three gyros wobble slightly when the rig changes directions. Sensors measure the wobbling and feed the data to microprocessors that in turn use high-speed electric motors to move the camera and offset the unwanted motion.
The second-generation technology -- what Mr. Chamberlain calls a sense-and-react system -- has only about half the stability of the original Wescam, so it cannot be used with lenses with very high magnification. But for the Orange County Sheriff's Department, it is unquestionably an improvement over using hand-held binoculars from a helicopter.
''At 1,500 feet we're not reading license plates, but we can tell if it's a man or a woman on the ground,'' Sergeant Sheer said.
Like many systems used by police forces, one of the two Wescam systems owned by Orange County has a night vision camera that creates images by capturing the infrared radiation emitted by warm objects, including people.
But a United States Supreme Court ruling last June has forced the Orange County Sheriff's Department and other police forces to change the way they use those thermal imaging cameras. The court said that the police could not train thermal imaging cameras on private homes without a warrant.
Mr. Steinhardt of the A.C.L.U. said he would like to see legislators, rather than the courts, come up with specific rules for police use of helicopter camera systems. The A.C.L.U. does not oppose the use of cameras ''under the rare circumstance that the police might be legitimately in pursuit of a hot suspect,'' he said.
''But in the end, that's not how it's going to be used,'' he added. ''It's going to be used in ordinary law enforcement, and that's very different.''
It is also being used from ever greater distances. Four years ago Wescam introduced a third stabilization system that combines the reliability of cameras like those used by the Orange County Sheriff's Department while offering even greater stability than the original system. It replaces the spinning mechanical gyroscopes with fiber-optic gyros, which use bursts of laser light to calculate movements by the camera system in each direction.
Once measured, the movement is also offset with a new technology known as magnetic torque motors that can apply a force in a specific direction but allow free movement in all other directions.
Not only is the new system much faster, said Steven Tritchew, Wescam's chief technology officer, but it will also provide a steady image with the magnification of ''any lens being made.'' Practically speaking, atmospheric haze and, ultimately, the impossibility of seeing beyond the horizon are the only limits on how far it can see. ''We call it the ground-based Hubbell -- we can see a long way,'' Mr. Chamberlain said.
Certainly Lt. Keith Howland, a mission commander and tactical coordinatorbased at the Naval Air Station in Brunswick, Me., noticed a big difference after an old system in his P-3 Orion surveillance airplane was replaced by a turret with Wescam's new technology about a year ago. ''You wouldn't even place them in the same universe,'' he said.
While on patrol, Lieutenant Howland said, he can watch events on the ground ''well outside of visible range.''
Like many civilian cameras, the Wescam on the P-3 can be aimed by punching in Global Positioning System coordinates. Software allows it to track moving objects on the ground more or less automatically.
While his aircraft's camera system cannot match the broad sweep of surveillance satellites, Lieutenant Howland said that it had many other advantages. ''Basically we can be in real time on a target, see things at the moment they happen, and report it,'' he said. ''It's live video versus a picture.''
The systems can be costly, with the most advanced models costing as much as $650,000. But Wescam plans gradually to introduce variations on the new technology into all its markets, potentially giving police departments the same farsightedness. (The Raytheon Company recently introduced a fiber-optic gyro-stabilization system of its own. FLIR Systems of Portland, Ore., is also among the companies that make stabilization systems for police and military use.)
Mr. Chamberlain suggested that the most advanced technology might next go to an even more demanding customer than a police department chasing criminals or a military unit tracking terrorists: the broadcast news industry.
''From a pure image point of view, the military want uninterrupted imagery,'' he said, ''but if it bounces a little bit once in a while or there's a little bit of fuzz on it from interference for a second or two, that's O.K. In the broadcast industry, if it jiggles a little bit or has a bit of fuzz when someone's crossing the finish line, well, you might not get invited back.''
Correction: June 22, 2002, Saturday An article in Circuits on Thursday about stabilization technology for airborne cameras included a misspelling of the name of NASA's space telescope in a comment by Mark Chamberlain, president of Wescam, on his company's stabilized cameras. The name is Hubble, not Hubbell.