focal length

noun

: 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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The notes in the margins of that shooting script are full of lens focal lengths, camera angles, and distances that were key to the compositions of shots. — Sarah Shachat, IndieWire, 28 Feb. 2026 Supporting this is a multi-camera array designed to work across various focal lengths. — New Atlas, 27 Apr. 2026 Maksutov-Cassegrain is a catadioptric design that uses two mirrors to allow a long focal length to fit into a compact optical tube. — Harry Bennett, Space.com, 11 June 2026 That effect can bring a sense of depth to images, but seeing a full picture clearly typically requires you to combine multiple photographs that were shot at different focal lengths. — Jess Weatherbed, The Verge, 29 Dec. 2025 See All Example Sentences for focal length

Word History

First Known Use

1682, in the meaning defined above

Time Traveler
The first known use of focal length was in 1682

Rhymes for focal length

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Browse Nearby Words

focalize
focal length
focal plane
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Cite this Entry

“Focal length.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/focal%20length. Accessed 8 Jul. 2026.

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Kids Definition

focal length

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

Medical Definition

focal length

noun
-ˌleŋ(k)th How to pronounce focal length (audio)
: the distance of a focus from the surface of a lens or concave mirror
—symbol f

More from Merriam-Webster on focal length

Britannica.com: Encyclopedia article about focal length

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