The Ultimate Guide to Suspension and Handling: Part Six, Adding Negative Camber
If you have your stock/rubber bushings, chances are they've taken a beating and this bushing deflection is part of your problem (page 2, top picture), but it could be any combination that anyone has mentioned above. The idea of mounting a camera under there is a good idea, that or get on a creeper and have a friend tow you around while you look at it from underneath. J/K, don't do that.