Housing for SP-320?

[Larry C]

The actual lens bubble, at the closest point sits about 11mm from the port glass on the PT-030. There's about 5mm from the threaded ring to the metal lens base. I think these are apples and oranges, though. Probably the only valid comparison would be with two lenses designed for the same camera. Mine is for a Nikonos V. I don't know how much the distance affects focus on wide angle. According to Sea & Sea, at the lowest available f-stop, the 16mm will focus from 2.2' to infinity. That seems about right on my SP as well, though I might have even got closer than that. The Sea & Sea is a wet only lens. It will not focus out of water.

 

[gert7to3]

I think that intra lens system distance is what's causing the slight vignetting you mentioned. Ashame you needed a step up rather than a step down adapter. Though zooming probably gets you into a better part of the lens' field of view overall.

Do you set your camera to macro mode whilst using the W/A lens?

 

[RockyHeap]

What about these wide angle lens, they're 46mm which is the threaded portion of the PT-030 housing. Different W/A lenses too, from .75 scaled reduction to .42 reduced gain.

Or do you need a special "wet lens" and can't use some of these U/W? THANKS for the advice to us budding photo buffs.

http://www.bhphotovideo.com/bnh/controller/home?A=details&Q=&is=REG&O=productlist&sku=294241

http://www.adorama.com/CAWD46.html

http://www.dive-equinox.com/lenses.shtml

 

[gert7to3]

Unless the lens is designed to be a wet lens it will not work. The refraction of light is different in water from air. The coatings are stronger. The lens elements have to be sealed and protected from water.