focal plane


Definition of focal plane

: a plane that is perpendicular to the axis of a lens or mirror and passes through the focus

Examples of focal plane in a Sentence

Recent Examples on the Web One end of each cable was supported by an aluminum plate positioned at the focal plane of the telescope. Kyle Dawson, Scientific American, 1 May 2021 In confocal microscopy the focal plane is imaged with a single, intense point of light, centered between two cones of light that flood the rest of the sample. Jen Christiansen, Scientific American, 21 May 2013 The first-focal plane design lets the shooter take maximum advantage of the reference marks in the reticle. Will Brantley, Field & Stream, 21 Dec. 2020 While testing of the focal plane continues, the first images are a huge milestone. Ashley Strickland, CNN, 8 Sep. 2020 The camera’s focal plane, similar to the imaging sensor of a digital camera, is more than 2 feet wide and is made up of 189 individual sensors that each contribute 16 megapixels, reports Ashley Strickland for CNN. Alex Fox, Smithsonian Magazine, 10 Sep. 2020 Still, most new products in the riflescope category have traits that appeal to long-range shooters: first-focal plane reticles, tactical milling turrets, and ample adjustment ranges. Andrew Mckean, Outdoor Life, 20 Jan. 2020 The difference between focal planes becomes exaggerated at extremely close and far target distances—decreasing accuracy and obscuring the reticle. Michael R. Shea, Field & Stream, 3 Jan. 2020 The instrument has 5000 fibers attached to its 0.8-meter-wide focal plane. Daniel Clery, Science | AAAS, 11 Sep. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'focal plane.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of focal plane

1840, in the meaning defined above

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Time Traveler for focal plane

Time Traveler

The first known use of focal plane was in 1840

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Statistics for focal plane

Last Updated

13 May 2021

Cite this Entry

“Focal plane.” Dictionary, Merriam-Webster, Accessed 22 Jun. 2021.

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More Definitions for focal plane

focal plane


Medical Definition of focal plane

: a plane that is perpendicular to the axis of a lens or mirror and passes through the focus


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