How to capture the fisheye image in the real scene?

Take the interchangeable lens suitable for 35mm SLR camera as an example. Fish-eye lens is a kind of ultra-wide-angle photographic lens with short focal length, and its focal length is about 6- 16mm. "Fish-eye lens" is its common name. In order to make the lens reach the maximum photographic angle, the front lens of this kind of photographic lens protrudes to the front of the lens in a parabolic shape, which is quite similar to the fish's eyes, hence the name "fisheye lens".

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.

The size of fisheye lens is very large. Take the fisheye lens for a 35mm single lens reflex camera as an example. The fisheye lens is installed on the body of a smaller 35mm single-lens reflex camera, which has a feeling of "big head (lens) and small body (body)", and the weight of the fisheye lens is not light (for example, the manual focusing fisheye lens of Nicol 6mm /F2.8 weighs 5,200g). As mentioned above, the front lens of the fisheye lens has a large diameter and is thrown in front of the lens, so this lens cannot be equipped with a filter like a normal lens. Fisheye lenses usually use a built-in filter. According to the shooting needs, the photographer manipulates the filter conversion ring on the lens to convert the required filter into the shooting light path of the lens. The front lens of fisheye lens is a very important lens in the whole lens. Because it is thrown in front of the camera, the photographer should pay special attention not to collide with the camera when shooting (especially when shooting close to the subject). In addition, when some old fisheye lenses are connected to a 35mm single-lens reflex camera, the back of the lens is deeply inserted into the camera body, and the mirror of the camera must be turned up and locked, and the pentaprism viewfinder of the camera will not be used, so it is necessary to set an additional viewfinder on the camera to take pictures.