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back focus

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noun Photography.
the distance between the back surface of a lens and the focal plane when the lens is focused at infinity.
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QUIZ YOURSELF ON "WAS" VS. "WERE"!
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“Was” is used for the indicative past tense of “to be,” and “were” is only used for the subjunctive past tense.

Origin of back focus

First recorded in 1895–1900
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022

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