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  2. Mirror image - Wikipedia

    en.wikipedia.org/wiki/Mirror_image

    A mirror image (in a plane mirror) is a reflected duplication of an object that appears almost identical, but is reversed in the direction perpendicular to the mirror surface. As an optical effect , it results from specular reflection off from surfaces of lustrous materials, especially a mirror or water .

  3. Image formation - Wikipedia

    en.wikipedia.org/wiki/Image_formation

    The ratio of the height of the image to the height of the object is the magnification. The spatial extent of the image surface and the focal length of the lens determines the field of view of the lens. Image formation of mirror these have a center of curvature and its focal length of the mirror is half of the center of curvature.

  4. f-number - Wikipedia

    en.wikipedia.org/wiki/F-number

    The blur-optimal f-stop varies with the lens design. For modern standard lenses having six or seven elements, the sharpest image is often obtained around f /5.6 – f /8, while for older standard lenses having only four elements (Tessar formula) stopping to f /11 will give the sharpest image.

  5. Virtual image - Wikipedia

    en.wikipedia.org/wiki/Virtual_image

    The image in a plane mirror is not magnified (that is, the image is the same size as the object) and appears to be as far behind the mirror as the object is in front of the mirror. A diverging lens (one that is thicker at the edges than the middle) or a concave mirror forms a virtual image. Such an image is reduced in size when compared to the ...

  6. Cardinal point (optics) - Wikipedia

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

    A system is focal if an object ray parallel to the axis is conjugate to an image ray that intersects the optical axis. The intersection of the image ray with the optical axis is the focal point F ′ in image space. Focal systems also have an axial object point F such that any ray through F is conjugate to an image ray parallel to the optical axis.

  7. Real image - Wikipedia

    en.wikipedia.org/wiki/Real_image

    A real image occurs at points where rays actually converge, whereas a virtual image occurs at points that rays appear to be diverging from. Real images can be produced by concave mirrors and converging lenses, only if the object is placed further away from the mirror/lens than the focal point, and this real image is inverted. As the object ...

  8. Reciprocity (photography) - Wikipedia

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

    In photography, reciprocity is the inverse relationship between the intensity and duration of light that determines the reaction of light-sensitive material. Within a normal exposure range for film stock, for example, the reciprocity law states that the film response will be determined by the total exposure, defined as intensity × time.

  9. Magnification - Wikipedia

    en.wikipedia.org/wiki/Magnification

    A telescope, which uses its large objective lens or primary mirror to create an image of a distant object and then allows the user to examine the image closely with a smaller eyepiece lens, thus making the object look larger. A microscope, which makes a small object appear as a much larger image at a comfortable distance for viewing. A ...