Focus evaluation method of the optical system, adjustment method, the adjustment devices, and charts devices

摘要

PURPOSE: To provide evaluation method and device of the position of the best image surface which can be evaluated easily and quickly. CONSTITUTION: The system is provided with a chart plate 11 where an edge image 13i can be formed, an optical system 15 where the image of the chart plate 11 can be formed, a light reception member 17 for converting an edge image 13i which is laid out at a position where the edge image 13i of the above chart plate 11 can be formed or near the position, and a sampling circuit for sampling an electrical signal outputted by the light reception member 17 in a direction crossing the edge image.