Choosing a first dome

[decidedlyodd]

I recently got my first underwater DSLR setup (Canon T2i/550D in Nauticam housing). I'm starting out with macro since it's more useful for local conditions and creatures, but I'm planning to add a wide-angle setup soon for an upcoming trip.



Based on everything I've read, I'm planning to start out with the Tokina 10-17 fisheye lens. However, when it comes to a dome port, I'm not really sure what to do. Is one of the 100mm/4" minidomes (acrylic or glass) a good place to start? Or would a larger 6" or even 8" dome be a better first choice?

 

[Thalassamania]

I can not speak to your exact setup, but here's the general skinny: you want to get the entrance pupil of your lens (that's the center of the len's aperture diaphragm)as close as possible to the center of curvature of the dome, that said, the greater the radius of the dome the less critical being at exactly the center of curvature becomes, larger domes are, "more forgiving," but of course are more unwieldy to use.

 

[pooley]

It depends on what you plan on shooting. If you're going for close focus wide angle (CWFA) then a 4" minidome should suffice. Over/unders will need the bigger dome, and if its 'general' wide angle, then againg, the larger is probably the better where corner sharpness is concerned

 

[Onewolf]

I have a Nauticam 550D with the Tokina 10-17 and a Zen 100mm glass dome. It is very sharp in the corners and it is much easier to pack/travel with the small dome versus the 8"+ domes. However.... the small dome works only with the Tokina 10-17 and it is not as good for over/under shots. For _me_, I think the advantages outweigh the disadvantages