I would like to buy a lens that creates a fish eye effect. However, when I look it up, it comes up with all different prices and all different names. I have a proper Canon camera and I was wondering what the specific name for a fish eye effect lens is, and what the approximate cost is likely to be?
There are various types of fisheye lenses and, to complicate matters further, the results change with sensor size, although there are fisheye lenses designed for APS-C cameras only that will not work on a full-frame.
A circular fisheye produces a circular image with usually a 180° degree field-of-view both horizontally and vertically. A rectangular fisheye produces a rectangular image and so the field-of-view can vary more, although 180° diagonally is more common. Some lenses have a wider or narrower view-angle, so check the specifications. Anything too wide is very hard to use since part of you such as your feet or a tripod used with be in the frame and it takes some work to edit them out.
If you use the Lens Search Tool on my site, you can easily find out what fisheye lenses exist for your camera. Just enable the fish icon and choose the lens mount to start. You can also restrict it to some brands and to Full-Frame if that is what you need.
Right now, if you search for EF-mount fisheye lenses, there are 9 results. Only 2 from Canon. Look at the row that says Perspective to see what type of fisheye each lens is. As the name part, you can see from the search results that they all include the word Fisheye in the name, while Tokina writes it like a compound word: Fish-Eye.