I've never had a problem with light leaks on my KO Rapid. I check all my cameras at least twice annually by inserting a bare bulb flashlight (mine is a Mini-Mag Lite with the lens cover removed) into the body, first from the front with the lens out, then from the rear with the back removed and a lens in place. In a dark room it is fairly easy to detect leaks. I move the camera on all axis and look for pinpoints projected on the walls or ceiling.