The Nikonos V is probably the most in the successful line of Nikon's underwater division. Superior to all the preceeding Nikonos' and more rugged and realistic than the Nikonos RS (that lasted 2 years), the Nikonos is one of a kind. Other underwater cameras don't have the depth rating, and no other has anything close to the quality achievable with a Nikonos. Even on land, this camera beats every other camera I have ever seen in terms of picture clarity and quality.
I use my Nikonos regularly, and it has never caused me any problems. Minimal maintenance, such as immediately washing with fresh water and periodic greasing of the O-rings, has kept my camera in new condition. Many accessories are available for this system, such as strobes, viewfinders, lenses, and extension tubes which let even beginning underwater photographers take remarkable pictures whether diving or snorkeling.
The hardest part about using a Nikonos is learning to judge distance and exposure levels underwater. The camera has a built in light meter which works well, but sometimes doesn't achieve the desired effect with the strobe. Judging distance is something you will go through many many rolls of film before you come close to perfecting it. Even after using my Nikonos regularly for 7 years now, I still throw away about a third of the underwater pictures I take with it. The remaining pictures, however, are something to behold!
I don't think true underwater cameras will be around much longer, as housings seem to be the way to go. With a housing, a standard land camera can be taken underwater with autofocus to guarantee more consistent shots. A dry lens is also significantly cheaper and easier to get than an underwater lens. For quality though, I am sure the Nikonos wins.
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