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Examples of focal length in a Sentence
Recent Examples on the Web
With its relatively short focal length and modest aperture, planets appear small and show little detail.
—PCMAG, 16 May 2024
Resolution begins to dip around f/16 at all focal lengths due to optical diffraction, with pictures looking soft at the smallest f-stops.
—PCMAG, 22 Mar. 2024
In this equation, s stands for sensor dimension in millimeters and f is the focal length of the lens in millimeters.
—Michael E. Bakich, Discover Magazine, 24 Feb. 2024
Wide-open resolution is a little better (4,200 lines) at the 50mm focal length, and the lens delivers similarly strong results stopped down as at 28mm.
—PCMAG, 28 Mar. 2024
The interference of these fields produces new focal zones, allowing the lens to encode several focal lengths in a single pupil, resulting in multifocality.
—William A. Haseltine, Forbes, 26 Feb. 2024
Use the formula in No. 14, but insert your scope’s focal length for f.
—Michael E. Bakich, Discover Magazine, 24 Feb. 2024
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
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
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 10 Jun. 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
More from Merriam-Webster on focal length
Britannica.com: Encyclopedia article about focal length
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