focal length

noun

Definition of focal length

: the distance of a focus from the surface of a lens or curved mirror

Examples of focal length in a Sentence

Recent Examples on the Web

The Sol, which is available starting today for $199.95, is available in a 45mm focal length for Canon EF, Nikon F, Sony A, Pentax K, Sony E, and Fuji X mounts, and a 22mm version for Micro Four Thirds. Dan Seifert, The Verge, "Lensbaby’s new Sol lens makes quirky images," 7 Aug. 2018 There are currently 16 operational telescopes of different sizes that make up the LCO, ranging in focal length from 2 meters to 0.4 meters, with more telescopes planned. Jay Bennett, Popular Mechanics, ""Brightest Supernova Ever" Turns Out to Be a Star Ripped Apart by a Supermassive Black Hole," 12 Dec. 2016 The shift from lens width to focal length likely arose in Hollywood for reasons of precision. Allain Daigle, The Atlantic, "How the 50-mm Lens Became ‘Normal’," 13 May 2018 The comparison of normal vision with focal length, rather than other forms of measurement, persists because of how lenses came to be produced and used in standard practice. Allain Daigle, The Atlantic, "How the 50-mm Lens Became ‘Normal’," 13 May 2018 In the 2016 tests, images were collected through conventional DSLR cameras set up for multiple focal lengths across both the visible and infrared spectra to simulate plenoptic capabilities. Russell Brandom, The Verge, "New Homeland Security system will bring facial recognition to land borders this summer," 5 June 2018 Over time, though, lenses came to be measured by the distance of their focal length. Allain Daigle, The Atlantic, "How the 50-mm Lens Became ‘Normal’," 13 May 2018 The ideal lens focal length would be in the 400mm to 600mm range on a 35mm SLR, less on APC cameras with smaller sensors. Michel Fortier, San Antonio Express-News, "Express-News photo editor explains how to photograph the super blue blood moon," 30 Jan. 2018 The lens was manually focused at infinity, zoomed to a 300 mm focal length, and the camera was set at f/10, 1/250 seconds and ISO-400. Kevin Ambrose, Washington Post, "Relive the solar eclipse in this timelapse over Washington, D.C.," 1 Sep. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'focal length.' 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 length

1682, in the meaning defined above

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Last Updated

10 Jan 2019

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Time Traveler for focal length

The first known use of focal length was in 1682

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More Definitions for focal length

focal length

noun

English Language Learners Definition of focal length

: the distance from the surface of a lens to the point of focus (sense 3)

focal length

noun
\ -ˌleŋ(k)th \

Medical Definition of focal length

: the distance of a focus from the surface of a lens or concave mirror symbol f

More from Merriam-Webster on focal length

Rhyming Dictionary: Words that rhyme with focal length

Britannica.com: Encyclopedia article about focal length

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