I'll diverge from the previous comments by suggesting a totally different lens. Nikon used to make a 70-180mm f4.5-f5.6 Micro-nikkor zoom. If you can find a used one in good condition, it will be far more versatile and useful than either the 60mm or 105mm lenses. [...]
This lens also performs very well behind a small diameter dome port which makes approximately 25% than behind a flat port. It is my single most used lens underwater.
Housings. [...] Subal has both auto-focus on and auto-focus lock controls. Subal also has a control that allows you to access both the programmable function and preview buttons on the front of the D800 (and D700) camera body. Having these allows you to utilize Nikon's "flash value lock" and not having your strobes fire without having to reach up and turn them off physically if you want to shoot a quick ambient light only shot, like a silhouette upward towards the water's surface. The viewfinder that comes with a Subal housing is not great, as is the case with many of the less expensive "basic" viewfinders. I really like the Nauticam viewfinders because they allow adjusting the viewfinder for your own eyes while you are underwater. Working with a local machine shop I was able to make a very nice adapter that allows me to mount the Nauticam viewfinders on my Subal housing.
[...] I'll be back in Florida just in time to go to the DEMA dive show - which is 6-9 November in Orlando. If there is any chance you might make it there, I would be happy to show you my housing and let you try it with a variety lenses and ports in a swimming pool. And if you would have the time, you could also try it on a real dive or two with me somewhere in Florida.
Thanks for you suggestion, Fred. In fact I don't know this lens that you mentioned and its versatility + the fact of being well accepted behind a small dome are very attractive. However, perhaps there are some other things to put on the balance. If it's an old Nikon model, there's no VR, right? At this moment I wanna something which I can use topside as well (at least for this first investment on a macro lens), then I guess that f/4.5-5.6 may be a bit dark for shooting macro whenever one doesn't wanna use a flash, no? And besides, I must confess: I try at maximum to avoid buying used gear because I don't think we can totally trust on them as you never know its previous history neither how much outworn are its electronic and mechanic parts. They may be OK for a while and suddenly show some issue which can be a headache to solve after.
Housings: yep, my first option until now (I still researching about…) is Subal too, for the same reasons you listed, despite its high cost. But what you said about the viewfinder is something new for me, I had no idea about it, so I thank you for the information, I'll double check it out and, whether I finally decide for Subal, probably I'll contact you again to have some other orientations about this adapter that you have developed together with your local machine shop. I'm in contact with Harald (from Subal's factory in Austria), who is helping me a lot about configuring my next gear setup, then, depending on him, I can say no doubts I'll also have a good after-sale support by email, which is very very valuable for me here in Brazil. Nevertheless, like there is no local tech assistance here, whenever I need something, I have to send goodies to the USA (which is the easiest country for me), so one more weight to be pondered. Then I take this opportunity to ask you about how does it work there in the USA? Florida is the best place in the USA for me to deal with something like this (due to the air ticket costs, lower percentages of sale tax and so on), so I'm considering about to buy my stuffs at (and, whenever my gear need maintenance be assisted by) Reef Photo. How do you like their job? Or would you recommend me any other place to buy and send gear for assistance in the USA? If you prefer answer these questions privately, please feel free to email me or send me a private message here through Wetpixel.
Anyway, stick with Subal is not yet definitely decided, I'm researching also about Nauticam, Seacam and Aquatica because I'll replace the whole rig - ports, domes, strobes (I wanna lighter ones than the two Ikelite I own) -, so there are many points to evaluate in addition to the performance of each brand (after-sale and assistance support, for example, something that I'm having some previous idea nowadays meanwhile I'm contacting factories to solve doubts about the products). Obviously get to the conclusion of the best cost/benefit is the main challenge because the total amount of money involved is considerable.
DEMA dive show: thanks for your niceness, I really would do my best to be there in order to try your gentle offer, but right now I can't tell you if I could go to Florida next November because I have a job with serpents at Pará (a state in the North of Brazil which is one of the nine brazilian states with Amazon biome) starting in October and for now I'm not able to know how long it will rest. Anyway, I'm sure I'm going to Florida sometime to buy my brand new gear, but I fear (in case of Subal) it must be pre-ordered, so, too late for testing your rigs before making my mind. Any other chance here which I could follow that I'm not getting to see now?