The records are admissible assuming a proper foundation has been laid. That means someone from the company must testify that the camera was in working order, had been properly calibrated and that the yellow light was properly timed for the speed limit. In some counties, such as SF, this is done routinely. In other counties you can catch the cops off guard by demanding the maintenance records for the red light camera at the time of the hearing.
Some Orange County courts have taken the position you've written about. But not all.
Partly because the courts are not consistent in their positions on the evidentiary issues of red-light camera cases, there is a lot of room for speculation and concern about whether to contest these. The very best advice you will find is at www.highwayrobbery.net You will find at that web-site an exhaustive discussion of all of the potential grounds for defense, including the foundational issue about which you asked, as well as forms, citations to previous court rulings and other very helpful suggestions. If you are serious about defending against one of these tickets, set aside an hour and go through this web-site carefully . (Note that the site is .net, NOT .com.)