Other reviewers have suggested that users either love or hate this camera. I fall in the middle ground because I love and hate it. However, I don't dislike it for the same reasons as the other reviewers.
I like it because it's tough! It's a workhorse that can take a beating. Maybe it's the rubber components in the body, but my Nikonos has bounced against many rocks during rough dives without a scratch. Maintenance after a dive is easy, but mandatory. I just take the o-rings out and put them in a zip-loc bag with some silicon grease (if you don't, the o-rings flatten out and could leak).
Other reviewers have found the manual focusing to be tricky and unconventional. However, I find the focusing to be relatively intuitive, especially with practice. In fact, I have used the Nikonos lens as a classroom tool to show how aperture selection affects depth of field. Some of the reviewers don't like the fact that you must estimate the distance-to-subject and anticipate that distance ahead of time. I have not found that to be a problem. When I am diving with my camera, I can usually judge ahead of time what sorts of subjects I will be shooting (whether close-up or otherwise). I pre-focus the lens to what I think I will be concentrating on. The location, visibility of the water and other environmental conditions often dictate the subject matter anyway (e.g., if the vis is bad, I'm shooting close-ups that day). I do agree that autofocus would be nice. However, when you've kicked up a lot of sand or silt, even the best autofocus camera will have a hard time focusing.
What I really dislike about the camera is how awkward it is when it is attached to a strobe. It not only adds to the overall weight of the camera, but it makes it difficult to swim. The strap attaches to the camera body and the strobe falls forward if you take your hand off the handle. Let's face it, underwater, you will need both hands sometimes. Incidentally, the strap that came with the camera is pathetically flimsy.
Attachments to the camera (macro kits, extension tubes) are easier to come by now E-bay is here. If you use a wire close-focusing frame to help compose shots, it really makes focusing macro work much easier.
I have owned my Nikonos V for about a decade. I didn't learn until I had had it for 6 or 7 years that Nikon recommends having the camera serviced annually. Servicing the camera costs between $75 and $150, for starters, means having it pressure tested. The repair shop will place it in a pressure chamber and simulate a deep dive down to about 150'. If it fails (mine did not), then they will replace the inner o-rings. The camera has two sets of o-rings, a set that the user changes, and a set that a repair shop must change.
Maybe an annual checkup isn't such a bad idea, but that's a lot of money to spend each year. Of course, mine does not get used as much as I would like, so maybe the maintenance is not quite so necessary. Cost of annual checkups (and whether to get them) should be a consideration for a prospective buyer.
This is not a camera for amateurs, I guess. The price would suggest that. However, it is a tough, durable piece of equipment that lasts.
As a side note: I had my Nikonos V and SB-101 strobe for about 7 years before there was a recall on the strobe. Nikon replaced my SB-101 for free with an SB-105 strobe that is bigger, brighter and has several more features. Of course, it took them about 8 months to send me the new one.
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