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 The illustration shows an eclipse at different focal lengths on a full-frame and a crop-sensor DSLR. Michael E. Bakich, Discover Magazine, 24 Feb. 2024 The lens focuses to about 9.8 inches (measured from the sensor) throughout its zoom range, so its largest macro magnification is at the 18mm focal length. PCMAG, 6 Feb. 2024 The focal length should be labeled somewhere on the eyepiece. Mike Lynch, Twin Cities, 14 Jan. 2024 In the larger Pro Max, the extra space allows Apple to step up to a 5x telephoto lens at a 120 mm focal length. Andrew Cunningham & Samuel Axon, Ars Technica, 12 Sep. 2023 The Pro Max camera boasts a 5x optical zoom, and allows for 120mm focal length. Byrachyl Jones, Fortune, 12 Sep. 2023 Because digital sensors are much smaller, a shorter focal length is required, demanding in turn a much smaller pinhole. IEEE Spectrum, 27 Aug. 2023 There’s noticeable natural bokeh (depth-of-field blur) in photos due to the focal length, image sensor size (1/1.3-inch) and fast f/1.5 aperture. Ben Sin, Forbes, 18 Dec. 2022 This creates enough separation between the lens and the sensor to enable the longer focal length. Jay Peters, The Verge, 18 Sep. 2023

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'focal length.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

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 18 Mar. 2024.

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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