A camera has a photometry section. The photometry section measures brightness of field when an aperture member is of a predetermined first aperture caliber which is a relatively large aperture caliber, and measures the brightness of field in halfway through change over of the aperture member from the first aperture caliber to a predetermined second aperture caliber which is relatively smaller than the first aperture caliber when a photometry of the brightness of field is impossible because of an exposure over with the first aperture caliber.