The lens illustrated is the type usually fitted to an SLR camera. It encompasses more or less the same view you see with one eye closed. The information on the front of the lens gives its focal length (50mm), maximum aperture (f2), maker’s name, brand name, and serial number. The side view shows scales for focusing, aperture setting and depth of field.
Modern lenses are made up from several glass elements ground to a precise shape and mounted inside a tube. Read the rest of this entry »
