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  2. Stadiametric rangefinding - Wikipedia

    en.wikipedia.org/wiki/Stadiametric_rangefinding

    The approximate range of an object one foot (30.48 cm) in height covering roughly 100 milliradians is 10 feet (3.048 m) or: Range (r) = approximate height of object (h) × (1000 ÷ aperture in milliradians (a)) r = h(1000/a) → where r and h are identical units, and a is in milliradians. r = h/a → where r and h are identical units, and a is ...

  3. 1951 USAF resolution test chart - Wikipedia

    en.wikipedia.org/wiki/1951_USAF_resolution_test...

    These 54 elements are provided in a standardized series of logarithmic steps in the spatial frequency range from 0.250 to 912.3 line pairs per millimeter (lp/mm). The series of elements spans the range of resolution of the unaided eye, down to the diffraction limits of conventional light microscopy.

  4. File:Foot width and length measurement for Mondopoint ...

    en.wikipedia.org/wiki/File:Foot_width_and_length...

    The following other wikis use this file: Usage on cs.wikipedia.org Velikost obuvi; Usage on de.wikipedia.org Schuhgröße; Usage on es.wikipedia.org

  5. Stereoscopic acuity - Wikipedia

    en.wikipedia.org/wiki/Stereoscopic_acuity

    Howard-Dolman test. Stereoacuity [1] is most simply explained by considering one of its earliest test, a two-peg device, named Howard-Dolman test after its inventors: [2] The observer is shown a black peg at a distance of 6m (=20 feet). A second peg, below it, can be moved back and forth until it is just detectably nearer than the fixed one.

  6. List of optometric abbreviations - Wikipedia

    en.wikipedia.org/wiki/List_of_optometric...

    the portion of the range of convergence that occurs in response to ... Cover test c/u: ... Visual acuity with eye chart at Distant 20 feet (6 m) and with (cc: Latin ...

  7. Visual acuity - Wikipedia

    en.wikipedia.org/wiki/Visual_acuity

    For 6/6 = 1.0 acuity, the size of a letter on the Snellen chart or Landolt C chart is a visual angle of 5 arc minutes (1 arc min = 1/60 of a degree), which is a 43 point font at 20 feet. [10] By the design of a typical optotype (like a Snellen E or a Landolt C), the critical gap that needs to be resolved is 1/5 this value, i.e., 1 arc min.

  8. Field of view - Wikipedia

    en.wikipedia.org/wiki/Field_of_view

    Field of view is the area of the inspection captured on the camera’s imager. The size of the field of view and the size of the camera’s imager directly affect the image resolution (one determining factor in accuracy). Working distance is the distance between the back of the lens and the target object.

  9. Eye relief - Wikipedia

    en.wikipedia.org/wiki/Eye_relief

    For a shooter, eye relief is also a safety consideration. If the eye relief of a telescopic sight is too short, leaving the eye close to the sight, the firearm's recoil can force the optic's eyepiece to hit and cut into the skin around the shooter's eye, leaving a curved scarring laceration on the medial end of the supraorbital ridge and the ...