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  2. Fisheye lens - Wikipedia

    en.wikipedia.org/wiki/Fisheye_lens

    A fisheye lens is an ultra wide-angle lens that produces strong visual distortion intended to create a wide panoramic or hemispherical image. [4] [5]: 145 Fisheye lenses achieve extremely wide angles of view, well beyond any rectilinear lens.

  3. Angle of view (photography) - Wikipedia

    en.wikipedia.org/wiki/Angle_of_view_(photography)

    So a standard 50 mm lens for 35 mm photography acts like a 50 mm standard "film" lens even on a professional digital SLR, but would act closer to a 75 mm (1.5×50 mm Nikon) or 80 mm lens (1.6×50mm Canon) on many mid-market DSLRs, and the 40-degree angle of view of a standard 50 mm lens on a film camera is equivalent to a 28–35 mm lens on ...

  4. Hemispherical photography - Wikipedia

    en.wikipedia.org/wiki/Hemispherical_photography

    Hemispherical photography, also known as canopy photography, is a technique to estimate solar radiation and characterize plant canopy geometry using photographs taken looking upward through an extreme wide-angle lens or a fisheye lens (Rich 1990). Typically, the viewing angle approaches or equals 180-degrees, such that all sky directions are ...

  5. Distortion (optics) - Wikipedia

    en.wikipedia.org/wiki/Distortion_(optics)

    Fisheye lenses are wide-angle lenses with heavy barrel distortion and thus exhibit both these phenomena, so objects in the center of the image (if shot from a short distance) are particularly enlarged: even if the barrel distortion is corrected, the resulting image is still from a wide-angle lens, and will still have a wide-angle perspective.

  6. Stereographic projection - Wikipedia

    en.wikipedia.org/wiki/Stereographic_projection

    Some fisheye lenses use a stereographic projection to capture a wide-angle view. [26] Compared to more traditional fisheye lenses which use an equal-area projection, areas close to the edge retain their shape, and straight lines are less curved. However, stereographic fisheye lenses are typically more expensive to manufacture. [27]

  7. 35 mm equivalent focal length - Wikipedia

    en.wikipedia.org/wiki/35_mm_equivalent_focal_length

    35 mm equivalent focal lengths are calculated by multiplying the actual focal length of the lens by the crop factor of the sensor. Typical crop factors are 1.26× – 1.29× for Canon (1.35× for Sigma "H") APS-H format, 1.5× for Nikon APS-C ("DX") format (also used by Sony, Pentax, Fuji, Samsung and others), 1.6× for Canon APS-C format, 2× for Micro Four Thirds format, 2.7× for 1-inch ...

  8. Luneburg lens - Wikipedia

    en.wikipedia.org/wiki/Luneburg_lens

    Cross-section of Maxwell's fish-eye lens, with blue shading representing increasing refractive index. Maxwell's fish-eye lens is also an example of the generalized Luneburg lens. The fish-eye, which was first fully described by Maxwell in 1854 [5] (and therefore pre-dates Luneburg's solution), has a refractive index varying according to

  9. Sigma 4.5mm f/2.8 EX DC Circular Fisheye HSM lens - Wikipedia

    en.wikipedia.org/wiki/Sigma_4.5mm_f/2.8_EX_DC...

    It is a circular fisheye lens, designed to project a 180-degree field of view in all directions onto a circular image. It is the first such lens to provide the complete circular fisheye effect on crop factor digital SLR cameras, which do not have a full 36x24mm sensor. [1] This lens is available in Canon, Nikon, Sigma, Pentax and Sony mounts.