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  2. Real image - Wikipedia

    en.wikipedia.org/wiki/Real_image

    In other words, a real image is an image which is located in the plane of convergence for the light rays that originate from a given object. Examples of real images include the image produced on a detector in the rear of a camera, and the image produced on an eyeball retina (the camera and eye focus light through an internal convex lens).

  3. Photographic lens design - Wikipedia

    en.wikipedia.org/wiki/Photographic_lens_design

    Example of a prime lens - Carl Zeiss Tessar. The type of lens being designed is significant in setting the key parameters. Prime lens - a photographic lens whose focal length is fixed, as opposed to a zoom lens, or that is the primary lens in a combination lens system. Zoom lenses - variable focal length lenses. Zoom lenses cover a range of ...

  4. Cardinal point (optics) - Wikipedia

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

    For a single lens surrounded by a medium of refractive index n = 1, the locations of the principal points H and H ′ with respect to the respective lens vertices are given by the formulas = ′ = (), where f is the focal length of the lens, d is its thickness, and r 1 and r 2 are the radii of curvature of its surfaces. Positive signs indicate ...

  5. Lens - Wikipedia

    en.wikipedia.org/wiki/Lens

    An extended hemispherical lens is a special type of plano-convex lens, in which the lens's curved surface is a full hemisphere and the lens is much thicker than the radius of curvature. Another extreme case of a thick convex lens is a ball lens, whose shape is completely round. When used in novelty photography it is often called a "lensball".

  6. Conjugate focal plane - Wikipedia

    en.wikipedia.org/wiki/Conjugate_focal_plane

    In optics, a conjugate plane or conjugate focal plane of a given plane P, is the plane P′ such that points on P are imaged on P′. [1] If an object is moved to the point occupied by its image, then the moved object's new image will appear at the point where the object originated.

  7. Camera lens - Wikipedia

    en.wikipedia.org/wiki/Camera_lens

    The camera equation, or G#, is the ratio of the radiance reaching the camera sensor to the irradiance on the focal plane of the camera lens. [8] The maximum usable aperture of a lens is specified as the focal ratio or f-number, defined as the lens's focal length divided by the effective aperture (or entrance pupil), a dimensionless number. The ...

  8. History of photographic lens design - Wikipedia

    en.wikipedia.org/wiki/History_of_photographic...

    A single-element camera lens is as long as its focal length; for example, 500 mm-focal-length lens requires 500 mm from the lens to the image plane. A telephoto lens is made physically shorter than its nominal focal length by pairing a front positive imaging cell with a rear magnifying negative cell. The powerful front group over-refracts the ...

  9. Geometrical optics - Wikipedia

    en.wikipedia.org/wiki/Geometrical_optics

    Incoming parallel rays are focused by a convex lens into an inverted real image one focal length from the lens, on the far side of the lens. Rays from an object at finite distance are focused further from the lens than the focal distance; the closer the object is to the lens, the further the image is from the lens.