Patent attributes
Disclosed herein is a zoom lens, wherein a stop moves in an optical axis direction n in a phase of zooming; a position of the stop in a telephoto end is located on an object side with respect to a position of the stop in a wide-angle end; an opening size of the stop is controlled in conjunction with the zooming so that an open F number becomes approximately constant in a range from the wide-angle end to a specific intermediate focal length; the opening size of the stop is made approximately constant in a range from the specific intermediate focal length to the telephoto end so that the open F number is changed; and the specific intermediate focal length fulfills the following conditional expression (1), wide-angle end focal length×1.5<specific intermediate focal length<telephoto end focal length/1.4 . . . (1).
