— the presence of a fisheye lens in the camera. Such a lens provides a very wide field of view — about 180 ° in all directions. Thanks to this, you can, for example, mount the camera on the ceiling and cover the entire room with it. At the same time, such models are much cheaper and more compact than devices with panoramic shooting (see the relevant paragraph), since there is only one lens in the fisheye camera. However fisheye optics give strong distortions at the edges of the image; however, this point is rarely critical in fact, and fisheye cameras are very popular in modern surveillance systems.
