Underwater shooter here.
>>4014551>>4014770I just took the plunge, so to speak, into these, found a mint Nikonos II with the 35. Bought the 15 and 28 for it.
Few things about these. Grease the seals before you take it in the water. The lens has its own seal and the top of the body on the I, II and III lifts up and has its own seal. They are likely to be original. Use Ikelite seal grease made for their housings, it works great. Let sit 24 hours, then check. Make sure no debris is on the seal area. The Ikelite grease works like Honda Shin-Etsu grease and fattens up the seals. Use the Ikelite stuff it's formulated for that specific type of rubber seal for underwater cameras.
It is a scale focus camera but the lenses have these neat moving scales like the old Zeiss Ikon or Kodak Retina Reflex lenses. It's a lot of fun to shoot on. The 35mm lens uses the exact same optical formula as the 35 made for the Nikon S rangefinder cameras of the period.
As for other cameras, Ikelite housings for older DSLRs are cheap now. I picked up my Ikelite Canon 20D housing for like 50 bucks and rebuilt it, and rebuilding them is pretty straightforward there's a lot of info online on how to do it. The 20D is a dinosaur by today's standards but if you put good fast lenses in front of it like my Sigma 24 1.8 EX you will still get good results and far better results than any of the compact underwater cams rated for like 10 or 30 feet. If you have to get one, I love my Fuji WP, fits in my pocket and has decent image quality. Also, Canon made underwater housings for their compact digitals including the S series and the S90 delivers almost DSLR image quality and they are cheap. Do not discount them, they have basic manual controls too and that aperture ring is nice.
If you wanna do Natgeo shit like diving into reefs, you will need an Ikelite DSLR housing.
As for film, the Nikonos can't be beat. Canon made something called a WP-1 point and shoot that yields decent images, pic related.