Patent ID: 6160671
Filing Date: 2000-12-12
Classification: G02B

Abstract:
A retro-focus lens comprising, in order from the longer conjugate length side of the lens:a first lens group of negative refractive power, said first lens group including, in order from the longer conjugate length side of the lens, a first lens element of positive refractive power and made of plastic with its surface on the longer conjugate length side of the lens being aspherical, a second lens element of negative refractive power and made of glass and with a concave surface on the shorter conjugate length side of the lens, and a third lens element having negative refractive power with a concave surface on the shorter conjugate length side of the lens, there being no additional lens elements between said first lens element and said third lens element;a second lens group of positive refractive power; anda third lens group of positive refractive power.