If your gear is packed on layer deep then the scanners shouldn't have a problem with it. I never take my camera gear out (except one awful time at CDG when I was forced to unload EVERYTHING). If the people operating the scanner can't figure out what it is, then they will hand check the bag. People aren't going to run off with your gear on its way into the scanner. (What could they do? If they grab something off the conveyor belt, then they'd have to run out of the area which would mean lots of people would be looking at them; the "danger" is after it goes through the scanner. There someone could easily pick something up. But, unless your bag screams expensive camera, there is no reason for someone to grab it). If TSA decides they want to rerun something, they will take the gear in question, put it in a tray and it goes right through the scanner (there may be one tray in front of it). A camera and two or three lenses shouldn't create any issues. I travel with a camera, an UW housing, three strobes, three lenses and two UW ports.