6" dome, diopter, and extensions

I have decided to purchase the Ikelite housing for my Nikon D90, Tokina 10-17, and Nikon AF-S 60mm f/2.8G lenses

I am looking for feedback regarding which dome, flat port, extensions, and diopters to purchase.

I would like to purchase the 6" dome for the Tokina 10-17 and was under the impression that I would need a diopter in order to lessen vignetting. I was told by the salesperson at Helix camera that there is not a diopter that works with the Ikelite 6" dome. Assuming this is true, how bad (if at all) is the vignetting if I use the Tokina behind the 6" dome with out a diopter? Do I also need an extension? If the vignetting is really that bad, should I consider the 8" dome for the Tokina or even consider a housing other then Ikelite that does accommodate diopters for the Tokina and 6" dome?

Thank you for your time!

The Tokina 10-17mm doesn't have a filter mount on the front so, as far as I know, there's no way to add a diopter. I use mine in a Ikelite 6" dome (#5503) where I removed the port shade and don't see any vignetting even at 10mm.

Thanks for your response, ATJ.

Are you using a 20mm extension with the 6"dome (#5503)?

No extension used at all. Just the lens with the camera and the #5503* with the housing.

* Note that my dome port is actually a #5503.20 which is a #5503 with a different shade but as the shade has to be removed for the 10-17mm, it is identical to the #5503 with shade removed.

I use the 5503 6 inch for the 10-17mm too and it works well, and actually has some advantages over the 8 inch dome due to its small size and its cheaper to boot.

Because the shade needs to be removed you need to be much more careful keeping the port dome from being scratched as its very easy to bump it, particularly on the bottom of the dome where the shade would normally reduce the possibility of impact.

Hi AMW, a 6" dome port is fine with this lens, no matter what brand of housing you would choose. Just to clarify a detail, the Tokina will not accept, but most important, does not require a diopter to be used behind the 6" dome or even a smaller dome such as the latest 4" offering on the market.

On the other hand, its very important that it be known that certain lens (quite a few actually) might require a diopter with the 6" dome port, and diopters do work with a 6" dome port, no matter what brand the port is. This diopter should be a +4 to counteract the negative dioptric strenght of the 6" dome (or in other words, reestablish the focus range to normal) a search through the Wetpixel archives will bring up many post on the subject of dome optics, diopter and positionning.

Cheers.