how good is the Oly 9-18 or the 12-50 in the Nauticam 4" dome port?

Hi guys!

I've got a trip coming up in late July to the Sea of Cortez on the Rocio Del Mar. Expected sightings underwater include sea lions (100% possibility), whale sharks (80-95% possibility), sharks (60-100% depending on species) and dolphins, humpback and sperm whales, and mobula rays (40-60% possibility).

I'm using a Olympus e-m5 in a Nauticam housing with an 8mm Panny fisheye and the 12-50 Oly lens in the dedicated port. Lighting is from two YS-01 strobes. I also own the 9-18 mm Oly lens.

My question is, "should I spring for the 4" dome port at this late date? Realizing that I can use the 9-18 and the 12-50 in that port is pretty good, but I won't have any time to practice with it before the trip and the cost ($480 not counting the zoom gears) will definitely cut into my trip funds. Without the zoom gears, I would be stuck with whatever setting I put the lens at before encasing it in the port, but in the 12-50 case, the 12mm setting might be pretty good. I am not sure how sharp either of these two lenses are underwater. Above water, I find the 12-50 to be quite sharp. I've only owned the 9-18 for a little while, but I don't use it too much as most of it's range is covered by the 12-40 PRO lens (used exclusively above water).

Would either of these possibilities be worth the cost at this time?

Thanks for your help!

12mm is not that wide may work for sharks but not for whales

You should look at the 4" wide angle port and buy a 3D printed gear for the 9-18 so that you can save some money

For sharks the 8mm fisheye won't be a good option just to wide occasionally will be ok but hit and miss

Your ideal lens would be the 7-14 panasonic that will allow you to cover both large animals and sharks in the mid distance however it costs a lot of money and you need a port you won't be able to use with the other lenses you have

Actually I find the combination very nice to shoot with. Was little bit disappointed with it, but after investing into +2 macro diopter the lens/port combination produces great results when shooting bigger objects. Corners are not the sharpest in CFWA photography, but still quite acceptable. I travel light with only this one port and use it for 9-18 and 60mm macro. For the price (and the fact it fits zoom gear for 14-42 that I already owned) I could not be happier. I posted some examples in this forum, but cannot find it now.