Would be interesting to compare the same image using the Tokina 10-17mm in Dx mode in the D800, Sigma 15mm FE and D800, and also the Tokina 10-17mm with the D7000. On paper there is a difference but what is it really like at the end of the day side by side?
It could be like comparing a block of wood under the accelerator of a BMW M3 and unblocked accelerator BMW M3 but driving them both in busy streets of Bangkok?
I have noticed a big difference with shooting from the maxium flash sync of 1/200th when I had the Nikon D90 and now the maxium flash sync of my Nikon D7000 of 1/320th. I mainly notice the difference my summer shots in clear shallow water with sunbursts and animals such as Manta Rays, Leopard sharks Turtles
Here are some unedited stock examples of shooting a f9 and 1/320th ISO100 with the Nikon D7000 and Tokina 10-17mm with Ikelite Ds161 strobes:
These are unedited and only resized to be uploaded
I had a quick look on the Ikelite website and it looks if you go the modular setup for the 60mm its going to cost you $350 vs $150 for the standard 60mm port. Benefit is that the modular port is glass front. Buy a new port just for the 105mm in standard is going to cost $150 vs $125 for the port body to add to your already 60mm modular setup. At the end of the day if you go modular you have a glass front and ability to change port bodys to accomodate different lens or a TC. The 60mm and 105mm modular port bodies are going to cost $425 (ikelite#5510.35,#5510.58.#5510.22) vs two standard ports at $150 each ((#5505.5, #5502.41). You can always troll for them second hand on ebay or classified sections which might help out in the money department.
You can get adapters for the Subsee and both ikelite modular and standard ports. I think reefnet seel them for $200 and $250 respectively.
Regarding the Tokina 10-17mm FE you have to shoot this lens in a dome. I have no experience with the Precision 5inch dome but it looks like a great setup for the Tokina and Ikelite especially if you want to add a TC later and shoot CFWA. If your into wrecks and big animals I would recommend the Ikelite 8inch dome as it would accomodate other lenses as the Precision dome is designed for just the Tokina 10-17mm.
The standard ikelite ports come with zoom gear from memory but I dont know what they do with the modular port setups.
UWPhotoNewbie I am just looking at what you think the adavantages the D600 over D800. Most of the advantages you mentioned dont really apply to a camera used underwater.
1. D800 has 36MP vs 24MP on the D600. Well if 36MP is too much to deal with you can always reduce the image size on the D800 to Medium and have a 20.3MP image size. If you want to go back to 36Mp its a simple change especially in the future. You cant do this with the D600 as your stuck with 24MP
2. High FPS isnt an issue underwater as you can only shoot as fast as your strobes can reload (unless you shooting without strobes alot........honestly who is)
3.Dumb green mode wont work underwater
4.Matching memory cards.......big deal these days with cards being so cheap
5.Lighter and small isnt going to make any difference when you put it in a housing
The advantages of the D800 are that there are housing already made for it available now. Higher flash sync which is an important factor when it comes to deciding a camera especially with wide angle. More AF point and better AF. Just the alone are more important advantages over the D600.