Optical element, holding structure for optical element, and image pickup apparatus

摘要

In an optical element composed of an entrance refractive surface, an exit refractive surface and a plurality of internal reflective surfaces provided between the entrance refractive surface and the exit refractive surface, a structure is provided for enabling the optical element to turn around a reference axis of the entrance refractive surface. Further, in such an optical element, an diaphragm member is disposed adjacent to the entrance refractive surface and is arranged to vary an aperture diameter thereof according to a movement thereof.