Some of the advantages of underwater digital cameras include:

- You can plug them into a TV.

- They are smaller and lighter than film cameras

- Bad shots can be easily deleted

- They can change resolution, which is useful for wide-angle photography in low lighting conditions underwater

- They produce better high-resolution shots

- They never run out of film (because they don't use film!)

- They have better depth of field (up to 4 times that of film cameras)

- They feature strobe shutter speeds as fast as 1/800th of a second, much faster than even the best film cameras

- Applications include sea mode, land mode, and external flash mode

Here are some examples of the best underwater digital cameras:

1. The Casio Exilim Zoom EX-Z1000

It has a 2. 8 inch LCD screen and 10 megapixels. Housing is required. Up to 3,2000 ISO. 3x optical zoom lens, and it even includes an anti-shake feature.

2. The Pentax Optio

It has a 2.5 inch LCD screen and 7 megapixels. It requires no additional housing. Usable for up to half an hour in depths of up to 5 feet. It can even be used for shooting underwater videos. Up to 1,600 ISO.

3. Fuji Film FinePix A400

Complete with waterproof housing, 4.2 megapixels. What's more, it's CHEAP - under $200 at the time of this writing).

4. SeaLife DC500

Includes both Land and sea flash modes. 5 megapixels, 3x optical zoom. Features an anti-shake function that compensates for movement by either the photographer or the subject.

The foregoing is only a small smaple of the total range of brands, cameras, and features available for photographers of almost any budget and any level of sophistication.