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 compact model gave him the right match of focal length and sensor size for concert pics. Kevin Purdy, Ars Technica, 17 Jan. 2025 On a telescope, magnification can be calculated by dividing its objective lens's focal length by the eyepiece's focal length, both expressed in millimeters. Jamie Carter, Space.com, 15 Jan. 2025 Sharp shooters with relatively fast aperture, producing clean shots at the wide (main and selfie camera), or 85mm telephoto (3X zoom) focal length. Ben Sin, Forbes, 3 Jan. 2025 The 28-300mm's OIS is effective enough to support crisp handheld exposures at 1/8-second exposure time at the 300mm focal length. PCMAG, 11 Dec. 2024 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

Dictionary Entries Near focal length

Cite this Entry

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