How does a lens adapter work?

How does a lens adapter work?

Added (1). I want to put a fisheye lens on my FinePix S4830, which is a point and shoot camera. I know point and shoot cameras don't have interchangeable lenses, but i heard about things called lens adapters. Can someone please explain how lens adapters work, and how I can get a fisheye onto my camera? Thanks in advance. I'm a complete camera noob by the way.

Several things here.

A lens ADAPTOR is a device used on SLR type cameras so one brand of lens can be used on a different brand of camera, such as using a Nikon lens on a Canon camera. So a lens adaptor is not at all the correct term for what you want.

What you are seeking is a glorified FILTER that screws onto the end of a lens. These filters are often called lenses, but technically they are not. Some may even call them adaptors, but again, that is an incorrect term.

It is simply a piece of glass or plastic that screws into the threads of a lens on a camera. These can be fisheye or telephoto or wide angle filters. About all the fisheye filter does is create distortion while giving a small degree of what a true fisheye lens does. However, the lens has to have FITER THREADS in order to use one of these filters. Your camera, (and no point and shoot camera of which I'm aware), has no such threads.

There's no fish eye filter / "adaptor" that can be used on your camera. There's software that can give the look of a fisheye lens, but it is NOT the massive degree of wide angle that is provided by a true fisheye lens.

It allows one lens to attach to a non-compatible camera. It's like attaching a Pentax screwmount lens to an Olympus micro four-thirds camera. Normally, you can't put them together. An adapter will make it happen. If you use an adapter, you will lose all automatic functions meaning you won't have autofocus and you will most likely have to determine exposure settings manually. In some instances, you will also lose the ability to focus to infinity. Unless you know exactly what you are doing (meaning you can shoot with confidence in manual mode), don't use adapters.