| 摘要 |
PROBLEM TO BE SOLVED: To solve the following problem: it is difficult to reduce the size of a lens system of brightness in which an F number is about 1.4 to 2.4. SOLUTION: In a lens system, a positive lens is disposed closest to an object side. A diaphragm is disposed at a widest air space in the lens system. The lens system satisfies the following conditional expressions: 0.05<L_1/L_TH<0.21, 1.5<L_TH/Y<8, wherein L_1 is an interval, in the front group as the lens group from a lens surface located closest to the object side to a lens surface located on the object side relative to the diaphragm in the lens system; L_TH is an interval from the lens surface located closest to the object side to a lens surface located closest to an image side in the lens system; and Y is a maximum image height. COPYRIGHT: (C)2011,JPO&INPIT |
