| 摘要 |
PROBLEM TO BE SOLVED: To provide a photographic optical system and a lens barrel in which vibration and impact are hardly caused and the magnification is made changeable, and also the occurrence of a flare is made suppressible. SOLUTION: This optical system is constituted of an objective lens and an image-formation lens and provided with a 1st lens group including a positive doublet obtained by joining a positive lens and a negative lens, a 2nd lens group including a negative joined meniscus lens whose concave surface faces to the 1st lens group side, and a 3rd lens group including a doublet, and an intermediate image is formed in space between the 1st and the 2nd lens groups, and the following conditions (1) and (2) are made to be satisfied: (1) 0.25<=F/FO<=1.5 and (2) 0.15<=D1/D<=0.4.
|
