Photographic lens

Abstract

Abstract PURPOSE: To provide the ultra-compact lens of telephoto ratio about 1.0, angle of view 60° or more abd F-number 3.5 by providing the 1st group of a positive meniscus lens whose convex face is directed to the object side, the biconcave 2nd group, the biconvex 3rd group and the 4th group of a negative meniscus lens in such a manner as to satisfy the specific conditions. CONSTITUTION: The lens is so made as to satisfy the conditions of formula I among the focal length f of the entire system, the combined focal length f 123 of the 1st, 2nd and 3rd group lenses, the focal length f 4 of the 4th group lens, the wall thickness d 3 of the 3rd group lens and the air spacing d 6 between the 3rd group and 4th group lenses. Such constitution yields the ultra-compact photographic lens of telephoto ratio about 1.0, angle of view 60° or more and F-number 3.5. COPYRIGHT: (C)1980,JPO&Japio

Inventors

• 👤 Toshihiro Imai
• 👤 Hiroshi Takase

Bibliographic Details