equivalent focal length


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equivalent focal length

[i′kwiv·ə·lənt ′fō·kəl ‚leŋkth]
(optics)
The focal length of a thin lens which forms images that most nearly duplicate those of a given compound lens, thick lens, or system of lenses.
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While the instrument has an equivalent focal length of 53.
The SD500 Digital ELPH also features a retractable 3x optical/4x digital zoom lens with a 35mm equivalent focal length of up to 37-111 mm, making it ideally suitable for a wide range of photographic applications from landscapes and snapshots to portraits and macro at a working distance of under four inches from the subject.

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