Compact zoom lens with short back focal distance

摘要

A compact zoom lens is constructed with, from front to rear, first, second and third lens units of positive, negative and positive refractive powers, respectively. A diaphragm is positioned in or adjacent the second lens unit. The second lens unit and the diaphragm are stationary. When zooming from the wide angle end to the telephoto end, the first and third lens units are axially moved in such a manner that each of the separations between the first and second lens units and between the second and third lens units is increased monotonically.