equivalent focal length


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equivalent focal length

n
(General Physics) optics the ratio of the size of an image of a small distant object near the optical axis to the angular distance of the object in radians

equivalent focal length

The distance measured along the optical axis of the lens from the rear nodal point to the plane of best average definition over the entire field used in a camera. See also focal length.
References in periodicals archive ?
The DC240 has an ISO rating of 140 and is fitted with a lens giving an equivalent focal length of 39-117mm on a 35mm camera.
In either case the equivalent focal length is 96 inches.
The PL200 also incorporates a powerful 7x optical zoom lens (35mm film equivalent focal length of 31mm-217mm) that puts consumers in the middle of the action.

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