monocle(redirected from Monacle)
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(1) An eyeglass lens, with or without a frame, that is held in the eye socket.
(2) The simplest kind of camera lens, consisting of a single positive meniscus-type lens. It is used predominantly in inexpensive cameras for portrait and landscape photographs. The best image quality is provided by a convex-concave meniscus lens with its convex side facing the photosensitive layer and with a diaphragm located in front of the objective. Monocles have a small aperture ratio (not exceeding 1:8) and a small image angle (not exceeding 25°). A monocle is also called a landscape lens.