focal length

focal length Definition

focal length

noun

the distance from the optical center of a lens or curved mirror to the point where light rays from a very distant object converge

focal length Usage Examples

Preposition: of

Converse of object

have: A convex lens has a focal length of 150 mm.
extend: The larger blocking filter allows you to extend the focal length without vignetting but does not enhance detail or lower the bandpass.

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