It is a type of wide-angle lens used in photography to capture extremely wide and hemispherical images. Its focus length varies between 8-10 mm for circular lenses and 15-16 mm for full frame lens. Originally developed for use in meteorology and astronomy, it is used in planetariums and dome theatres to show pictures on a broad canvas.
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Charan Singh Death Anniversary: 29th May
Chaudhary Charan Singh was the leader of Lok Dal and former prime minister of India …