Imaging device

An imaging device comprising:

• an imaging optical system that is configured to collect light from a subject and to form a primary image of the subject;
• a microlens array having a plurality of microlenses that are two-dimensionally arrayed at a position of the primary image formed by the imaging optical system or a position conjugate with the primary image and that collect light coming from the imaging optical system;
• a relay optical system that is configured to relay the light collected by the microlenses and re-forms the primary image to form a secondary image;
• a light-receiving part that has a plurality of light-receiving elements disposed in an area corresponding to each of the plurality of microlenses, the plurality of light-receiving elements is configured to receive the light relayed by the relay optical system and to photoelectrically convert the light;
• and
• an adjusting unit that is configured to switch between a first layout state, in which the plurality of light-receiving elements and back focal positions of the microlenses are conjugate with each other, and a second layout state, in which the plurality of light-receiving elements and principal-point positions of the microlenses are conjugate with each other.