The indicator has an axis 1700, an indicator 1701 that is located near the center of the axis 1700 and that indicates the in-focus position, and indicators 1702 and 1703 that are located near respective ends of the axis 1700 and that indicate the back focus state and the front focus state, respectively. The indicator furthermore has a mark 1704 indicating the degree of focus of the right image, and a mark 1705 indicating the degree of focus of the left image, located near the top and bottom of the axis 1700 to indicate the positions thereof on the axis 1700.
FIG. 17A is an example of a first display format when both the right image and the left image are in an in-focus state (the defocus amount is 0 for both the right eye optical system 301R and the left eye optical system 301L). In this case, there is no difference in the degrees of focus between the right image and the left image, and thus the marks 1704 and 1705 are positioned to point to the same position on the axis 1700. Because the defocus amount is zero, the marks 1704 and 1705 are positioned so as to point to the position on the axis 1700 indicated by the indicator 1701. In this case, at least part of the indicator may be displayed using a different color, visual effect, or the like from the other display format, similar to the first display format used when in focus in the second embodiment.
