and rainfall amounts. In door's peepholes, to allow the viewer inside to see a wider view from the outside. Mapping function The subject is placed in the image by the lens according to the mapping function of the lens. The mapping function gives , the position of the object from the center of the image, as a function of , the focal length, and , the angle from the optical axis. is measured in radians. Other mapping functions (for example Panomorph Lenses) are also possible for enhancing the off-axis resolution of fisheye lenses. With appropriate software, the curvilinear images produced by a fisheye lens can be remapped to a conventional rectilinear projection. Although this entails some loss of detail at the edges of the frame, the technique can produce an image with a field of view greater than that of a conventional rectilinear lens. This is particularly useful for creating panoramic images. All types of fisheye lenses bend straight lines. Aperture angles of 180° or more are possible only with large amounts of barrel distortion. See also Azimuthal equidistant projection Dashcam Miniature faking Stereographic projection :de:Fischaugenobjektiv Fisheye lens with more information in German Notes References External links Fisheye projection theory List of all Current and all Affordable Photography Fisheye Lenses The New Fish List, Luca Vascon, 2021 Various fisheye projections Alternative archived URL Photographic lenses