No, it can be used with other adapters, Inon is just one. Fantasea lenses (which is nearly identical to the 105SD lens) and filters fit many Olys and Canons. I just need the OD size then.
Jack
The port has no threads but if it is simply the OD of the port that you need I can get that for you. No, the Inon 105AD lens is a bayonet mount that uses the AD adapter. The Inon 100 type have threads that fit I beleive the 67mm diamter. These I am not as familiar with since I have only held them in my hands once.
I looked for other adapters, I don't see them, perhaps I do not understand your needs.
The metal ring is 2 1/8 inches diameter. The upper portion of the metal ring is truncated. The port extension increases in diameter towards the case, cone shaped if you will. Again, neither the inner or outer portions of the metal port ring are threaded.
The Inon DC12 AD adapter slips over the port and then is held in place by a plate that extends under to the tripod socket and tray assembly. If you remove the screw from the tripod socket the cone shaped port extension allows the DC12AD adapter to slowly work forward and fall off or easily pull off by hand.
I just ordered and should recieve in a day or so the Ikelite housing for the Canon 570IS (I have two of them). This housing uses the 67mm thread ring. So, I have just the opposite problem, I will have to fabricate/machine/invent/dream an adapter or port or whatever to adapt the AD lenses to the 67mm threaded port.
One other thing, I have held the Fantasea housing for the Nikon P5100 but not side by side to my DC12 housing. It is my opinion --by eyeball--that the two ports are the same diameter or very very close and the metal ring sure looks the same--but--I did not do a side by side.
Good luck.
N