I went swimming with my Pentax K50 + DA*50-135 today.
Both body and camera are very well sealed. Once I put them underwater and moved around(violently) there weren't any visible bubbles coming out of neither.
The camera continued to function underwater.
But water still got through.
I found that during my ~30second test with the camera under water, water managed to seep in through the Focus Ring which ultimately made it's way onto the glass in form of a fine mist. There was also a small drop of water on the inside of the measuring display.
On the body however, the rubber sealings didn't manage to keep the water out of the PC and intervalometer port. The SD card slot was dry - it has visibly more protection. There were a few drops of water on the battery.
No water managed to get through the mount, it was completely dry.
I have the slight suspicion some water went in through the shutter and aperture selection scrolling buttons, as the aperture selection acted up at one point.
After giving the body a blower treatment, there seems to be no permanent damage.
The lens had some water in it which started misting the glasses. I removed the bottom part of the lens and used a blower to force a little air movement inside the lens. The glasses cleared up slowly and remained clear afterwards.
All signs of water have now disappeared and everything functions.
So to my disappointment I have to say: Pentax SLRs and lenses aren't waterproof enough to use them as underwater cameras
But they sure are weathersealed like crazy.