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 macro photos can be shot as 48-megapixel files, but all the other focal lengths have smaller sensors due to the cropping. Jakob Schiller, Outside, 23 Sep. 2025 Even though the aperture opens to f/1.4, the 12mm focal length simply doesn't provide enough compression for the effect when taking photos with a distant focus point. PC Magazine, 23 Sep. 2025 The company has been testing several new features, including major upgrades to video recording and a variable aperture system to give users more control over focal length. Bloomberg, Mercury News, 9 Sep. 2025 The cameras see major upgrades, with an 8x optical zoom offering the equivalent of a 200mm focal length. Aamir Khollam, Interesting Engineering, 9 Sep. 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

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Cite this Entry

“Focal length.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/focal%20length. Accessed 5 Oct. 2025.

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

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