What does the fisheye function of a digital camera mean and what is it used for?

Introduction to the fisheye lens: Take the lens suitable for 135-frame SLR cameras as an example. The fisheye lens is a short focal length ultra-wide-angle photography lens with a focal length of about 6-16 mm. "Fisheye" "Lens" is its common name. In order to achieve the maximum photographic angle of the lens, the diameter of the front lens of this photographic lens is very short and protrudes parabolically toward the front of the lens, which is very similar to the eye of a fish, hence the term fisheye lens. 2. The purpose of the fisheye lens: The fisheye lens can create a strong perspective effect when shooting close to the subject, emphasizing the contrast between the near and far objects, making the picture taken a shocking appeal; fisheye The lens has a fairly long depth of field, which is conducive to expressing the long depth of field effect in photos. The image taken with the fisheye lens is quite deformed and has a strong sense of perspective convergence. Directly attach the fisheye lens to the camera to capture distorted and exaggerated effects.