Patent ID: 8823860

Claim:
A camera comprising: a pupil split unit, which includes at least two holes to split a beam of light passing through an image-taking lens into at least two beams of light; a filter arranged at one of the at least two holes, reducing a quantity of light passing through said one of the holes; an image pickup unit taking an image with light passing simultaneously through the at least two holes of the pupil split unit; and a calculation unit calculating a focusing control state based on synthetic image data output as images, which are different in a quantity of light, passing through the at least two holes of the pupil split unit as taken by the image pickup unit, wherein the calculation unit performs a calculation regarding a focusing control direction based on a difference in a quantity of light of each image which is formed as light is split by the at least two holes, and wherein the focusing control direction is used to set a direction in which a focus lens is moved.