Patent Document ID: 4381888
Application ID: 06272379
Patent Status: 1

Claim One:
1. A large relative aperture, wide angle objective lens of the retrofocus type including, successively in the direction from front to rear, first, second and third lens groups, of which the first lens group has a negative refractive power and comprises, from front to rear, a positive meniscus lens convex toward the front, a negative meniscus lens convex toward the front, a negative meniscus lens convex toward the front, a positive lens and a negative meniscus lens convex toward the front, the second lens group has a positive refractive power and comprises a cemented bi-convex lens, and the third lens group has a positive refractive power and comprises, from front to rear, a cemented lens of a positive element and a negative element, a positive meniscus lens convex toward the rear, a cemented lens of a negative element and a positive element, and a positive lens, and a diaphragm positioned in a space between the second and third lens groups.