focal plane


nounOptics.
  1. a plane through a focal point and normal to the axis of a lens, mirror, or other optical system.: Compare principal plane.

  2. the transverse plane in a telescope where the real image of a distant view is in focus.

Origin of focal plane

1
First recorded in 1890–95

Words Nearby focal plane

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How to use focal plane in a sentence

British Dictionary definitions for focal plane

focal plane

noun
  1. the plane that is perpendicular to the axis of a lens or mirror and passes through the focal point

  2. the plane in a telescope, camera, or other optical instrument in which a real image is in focus

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