Housed Mirrorless cameras and underwater housings from Olympus have been revolutionizing the underwater photo world with their high performance, interchangeable lenses, great performance - all in a much smaller size.
Underwater Camera Floods: Avoiding the High Water Mark
No subject scares underwater photographers more than having an expensive housed camera turn into an aquarium. Even a bit of water can turn electronics into a corroded mess.
Here are a few general tips on maintenance that should help you avoid finding Nemo in your housing