Patent ID: 8174607

Claim:
An image pickup device comprising: a picture-taking lens; an image pickup element that receives light of an object image formed by the picture-taking lens; and a focus detection filter section, the focus detection filter section, from the side of the picture-taking lens in the following order, including: a field diaphragm that includes a plurality of first openings; a condenser lens disposed near the field diaphragm; a pupil division diaphragm that includes a plurality of second openings arranged at such intervals as to secure focusing accuracy; and a re-imaging lens group that includes a plurality of re-imaging lenses that are so arranged as to correspond to the second openings, the field diaphragm being disposed at a substantially conjugated position with the image pickup element, a plurality of the first openings being so formed as to allow two light beams that each pass through different areas of the picture-taking lens to enter the different re-imaging lenses after passing through the different first openings, the focus detection filter section being so disposed near the image pickup element and on an optical path between the picture-taking lens and the image pickup element as to be able to be inserted and withdrawn, and the focus detection filter section being inserted into the optical path when a focus is detected and being withdrawn from the optical path when a picture is taken.