Just returned from Bonaire where a fellow on the boat had the Backscatter system. According to him the vacuum caused a problem with his camera in that not all the buttons worked. His theory is that the vacuum caused the buttons in the camera to get sucked in a little bit which meant they did not meet up properly with the housing controls. Any comments on this?
While anything is possible, it is highly unlikely that the vacuum would cause an issue with the buttons. At -5 inches of Hg (the recommended vacuum to pull) is only 2.5 PSI or the equivalent to about 5 feet in water. So it's as if you're diving the housing 5 feet deeper than your depth.