Imaging optical system, imaging device, and moving object

The invention provides an imaging optical system, an imaging device and a moving object, which can realize a novel imaging optical system capable of reducing the influence of ghosting light. The imaging optical system forms an image in which an imaging target is set as an object on an imaging surface, in which a lens system and a filter are disposed from the object side toward the image side, the lens system has a five-group configuration, the filter has a parallel flat plate shape and is disposed so as to be orthogonal to the optical axis of the lens system, and the filter is disposed so as to be orthogonal to the optical axis of the lens system. The first group of the lens system is composed of a first lens which is a negative meniscus lens with a convex surface facing the object side, and the curvature radius R11 of the object side surface of the first lens, the focal distance f of the whole system, the distance Df between the object side surface of the filter and the image surface, and the full length L o