Sony RX100 versus Sony Nex5n

Is there anybody who can estimate or try to compare the advantages and disadvantages of that two setups:

1. Sony RX100 in Aquapazza housing + InonUWL H100+dome unit versus 2. Sony Nex5N in Aquapazza housing with Samyang 8mm and dome port ??

RX100 is a bit smaller

Nex 5N offer higher ISO

When I compared image sharpness of the 16mm pancake lens + wide angle converter on Nex5N with RX100 and Inon wet lens, then I did not found too big difference. But the Samyang 8mm lens seems to be a bit better, and would give wider view, instead of the RX100 plus Inon.

Disadvantages of Samyang 8mm is 30 cm focusing distance and manual focus.

Please give me some arguments to change the system or not.

I am interested mainly with WAL.

Other then camera differences the inon is a semi fisheye whilst the samyang is a real fisheye. If you need the additional field of view or you want to take over under shots the nex5 solution has an advantage

THX Interceptor. The wider field of view is the main reason, why I am looking for that setup.

I am only worry If I can handle with manual focus and manual aperture setup, when there is no wheel on the housing. So I have to choose aperture and focusing distance before diving.