A sighting device includes a fixed-position objective lens group lying on an optical axis, an eyepiece lens group lying on the optical axis, and a variable-position objective lens group lying on the optical axis and positioned between the fixed-position objective lens group and the eyepiece lens group. A variable-lens position of the variable-position objective lens group relative to the fixed-position objective lens group or the eyepiece lens group may be controllably varied. A mechanical aperture stop lies on the optical axis between the fixed-position objective lens group and the eyepiece lens group. A stop axial position and/or a stop size of the mechanical aperture stop may be varied according to the position of the variable-position objective lens group.