| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a close-up lens which can form an image capturing optical system having an effective F-number brighter than 3.0 when combined with a main lens, is capable of forming an image at an image magnification of approximately 0.2 or more, and yet has a sufficiently small thickness in a thickness direction of an image capturing device and a small diameter, and to provide an image capturing optical system and an image capturing device having the same.SOLUTION: A close-up lens CL comprises, in order from the object side, a first lens group L1 having negative refractive power, a second lens group L2 having positive refractive power, and a third lens group L3 having positive refractive power. The first lens group L1 comprises a single negative lens and satisfies the following conditional expression: -0.65<f1/f<-0.10...(1), where f1 represents a focal length of the first lens group L1 and f represents a focal length of the entire close-up lens system.</p> |
