What is the fisheye effect of photography?

? The biggest function of fisheye lens is its wide viewing angle, which can generally reach 220 or 230, creating conditions for shooting large-scale scenes at close range; The fisheye lens can produce a very strong perspective effect when shooting close to the subject, emphasizing the contrast between the near big and the far small of the subject, so that the shot picture has a shocking appeal; The fisheye lens has a large depth of field, which is beneficial to show the long depth of field effect of photos. There are two kinds of fisheye lens imaging, one is full of pictures like other lenses; The other imaging is circular. No matter what kind of imaging, the images taken with fisheye lens are quite deformed and have a strong sense of perspective convergence. Therefore, it is often used as a special effect lens, and an arm extending to the fisheye lens will appear twice as long as the original one.