The practical upshot of this is that you can get anything if you have the money. If not, you will be a thousand times better off with either a digital camera and a housing or a Nikonos V. The Nikonos has great super-ultrawide lenses since it's a viewfinder camera, plus they are specifically designed to be in contact with water rather than air. Plan about $100 for the camera plus about $200 for your lens of choice, plus strobe. For best digital results, plan on getting access to a Nikon 9000 scanner or a drum scanner. If you get a digital camera, it's essentially this or that, whatever you can get a housing for plus a superwide zoom plus matched dome. Plan on the order of $2500 for this, plus strobe for a DSLR, or $300 plus strobe for a P+S housing.
There's also the PiratePro housing, which is EXTREMELY promising if they ever get it off the ground. Essentially, it mounts Nikonos-V lenses on an Epson EP-1. As mentioned, the Nikonos-V optics are custom-designed for water and are amazing.
Anything beyond this will be extremely expensive. You should plan on 3-5k of expenses to procure a Rolleimarin or a Pentax 67 Marine housing. At least. Also, you only get 20 or 24 exposures, and they'll be less wide than is possible with digital/35mm. While it's possible, I don't regard this as a great option. Unless you are VERY experienced at underwater photography, the instant feedback of a digital camera is worth more than the resolution of medium format.
Last edited by PaulMD; 10-02-2011 at 10:36 PM. Click to view previous post history.