Sam Thompson , Feb 01, 2007; 02:23 a.m.
If the assistant or second shooter is an employee of yours then you retain copyrights because they are work for hire. If they are a contractor then the second shooter images are retained by them because they are a contractor barring a written agreement.
First shooters are better off using contractors rather than employing them because that limits their liability if the contractor does something negligently at the shoot. If the 2nd shooter damages property at the wedding the primary photographer can be sued for example.