If I put my plastic cosina 28mm on the K20D it might very well float, but lens up and body down
...not so good...and it wouldn't keep me floating. Would be interesting if they applied the same level of sealing on a DSLR as they do on the Optio W.... cameras, water proof to a few m. That would be something.
Once fell into a river with most of the lenses etc in water proof bags in the backpack, but the LX I was carrying got quite wet...not as wet as me since I tried to keep it out of the water even at the price of getting myself even more wet...but enough to make me very worried, but once I got myself into spare clothes and tested the camera it worked and still works. I wonder how good the current DSLR sealing is compared to the LX? Not that I'm going to test jumping into a melt water river again.