.... fisheyes are not universal..?
if you have any idea what you are commenting on than you should know, for example, when the HVX came out, no fisheye until the lens bastard and later on the manistream companies released models that would fit the HVX.
also, there is video and photography fisheyes, all with different focal lengths and apertures that only taylor to certain cameras.
so what exactly are you laughing at?