i dont have an hv40 but i dont htink you "swap lenses"...you just use the threads to screw them on? You need to buy a lens with the same thread size. you dont swap anything
hv40 has one lens, cameras with changeable lenses are $$$$$$
what you need is an adapter, its a second lens you screw to the front of the camera that modifies the angle such as fisheye, wide angle, telephoto or macro
he we go. most cameras have threads in front of the main lens. different cameras have different sizes for the lens. look on the side and it should give you a size. for example my gl2 has a 58mm lens size so i know if i want to get another lens that is the same size. you can get lens adapters so for can fit a different lens onto your cam so you can get a 42mm lens on you 58mm cam or whatever its not that hard just check to make sure that you are getting the right size or adapter so you can use whatever you just spent you hard earned $$$$$ on.