| 摘要 |
PROBLEM TO BE SOLVED: To provide an imaging optical system that is configured so as to allow light of a sufficient amount of light to reach a sensor arranged on an image plane even if a F-number is made small and a filter is arranged.SOLUTION: An imaging optical system comprises, arranged from an object side to an image side: a first lens that is a negative lens; a second lens that is a meniscus lens with a convex surface directed at the image side; a stop; a third lens that is a positive lens; a fourth lens that is the positive lens; or a combination of the fourth lens and a fifth lens that is the positive lens. Let a center thickness of the second lens be t2, and an entire focal length be f, the imaging optical system satisfies t2/f>1.2.SELECTED DRAWING: Figure 1 |
