varifocal lens

varifocal lens
A spectacle lens whose magnifying power varies from top to bottom, allowing them to be used for both distance use and for reading

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  • Varifocal lens — A varifocal lens is a camera lens with variable focal length in which focus changes as focal length (and magnification) changes, as compared to parfocal ( true ) zoom lens, which remains in focus as the lens zooms (focal length and magnification… …   Wikipedia

  • varifocal lens — kintamojo židinio objektyvas statusas T sritis fizika atitikmenys: angl. variable focus objective; variable focus lens; varifocal lens vok. Objektiv mit veränderlicher Brennweite, n; Varioobjektiv, n; Zoom Objektiv, n rus. вариообъектив, m;… …   Fizikos terminų žodynas

  • varifocal lens — |verē, |va(a)rē+... noun Etymology: vari + focal : zoom lens …   Useful english dictionary

  • varifocal — [ˌvɛ:rɪ fəʊk(ə)l] adjective denoting a lens that allows an infinite number of focusing distances for near, intermediate, and far vision. noun (varifocals) varifocal glasses …   English new terms dictionary

  • varifocal — adj. & n. adj. having a focal length that can be varied, esp. of a lens that allows an infinite number of focusing distances for near, intermediate, and far vision. n. (in pl.) varifocal spectacles …   Useful english dictionary

  • Zoom lens — Nikkor 28 200 mm zoom lens, extended to 200 mm at left and collapsed to 28 mm focal length at right A zoom lens is a mechanical assembly of lens elements for which the focal length (and thus angle of view) can be varied, as opposed to a fixed… …   Wikipedia

  • zoom lens — noun a camera lens that magnifies the image • Syn: ↑telephoto lens • Hypernyms: ↑camera lens, ↑optical lens * * * noun : a camera lens in which the focal length and the image size can be varied continuously so that the image remains in focus at… …   Useful english dictionary

  • Parfocal lens — A parfocal lens is a lens that stays in focus when magnification/focal length is changed. There is inevitably some amount of focus error, but small enough not to be considered significant.MicroscopyParfocal microscope objectives stay in focus… …   Wikipedia

  • lente varifocal — Eng. Varifocal lens Ver lente progresiva …   Diccionario de oftalmología

  • variable-focus lens — kintamojo židinio objektyvas statusas T sritis fizika atitikmenys: angl. variable focus objective; variable focus lens; varifocal lens vok. Objektiv mit veränderlicher Brennweite, n; Varioobjektiv, n; Zoom Objektiv, n rus. вариообъектив, m;… …   Fizikos terminų žodynas

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