Telescopic sighting device with variable exit pupil

1. A sighting device comprising:

a fixed-position objective lens group lying on an optical axis;

an eyepiece lens group lying on the optical axis;

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, wherein the variable-position objective lens group is a tumbler lens group, and wherein a variable-lens position of the variable-position objective lens group relative to the eyepiece lens group may be controllably varied; and

a mechanical aperture stop lying on the optical axis between the fixed-position objective lens group and the eyepiece lens group, wherein a stop axial position or a stop size of the mechanical aperture stop is varied according to the position of the variable-position objective lens group.

2. The sighting device of claim 1 , wherein the stop axial position of the mechanical aperture stop is varied automatically responsive to the position of the variable-position objective lens group.

3. The sighting device of claim 1 , wherein the stop size of the mechanical aperture stop is varied automatically responsive to the position of the variable-position objective lens group.

4. The sighting device of claim 1 , wherein the stop axial position or the stop size of the mechanical aperture stop, and the variable-lens position, are both changed automatically responsive to a user-operated magnification control.

5. The sighting device of claim 1 , further including

a mechanical linkage that varies the stop axial position or the stop size of the mechanical aperture stop, and the variable-lens position, responsive to a user-operated magnification control.

6. The sighting device of claim 1 , further including

a housing in which the fixed-position objective lens group, the eyepiece lens group, the variable-position objective lens group, and the mechanical aperture stop are mounted.

7. The sighting device of claim 1 , further including

a housing in which the fixed-position objective lens group, the eyepiece lens group, the variable-position objective lens group, and the mechanical aperture stop are mounted, and

an attachment on the housing adapted to attach the housing to a rifle.

8. The sighting device of claim 1 , further including

a housing in which the fixed-position objective lens group, the eyepiece lens group, the variable-position objective lens group, and the mechanical aperture stop are mounted, and

a magnification control that sets the stop axial position or the stop size of the mechanical aperture stop, and the variable-lens position, and wherein the magnification control is manually accessible outside of the housing.

9. A sighting device comprising:

a housing;

a fixed-position objective lens group within the housing and lying on an optical axis that extends lengthwise through the housing;

an eyepiece lens group within the housing and lying on the optical axis;

a magnification control that is manually accessible on an exterior of the housing;

a variable-position objective lens group within the housing and lying on the optical axis and positioned between the fixed-position objective lens group and the eyepiece lens group, wherein the variable-position objective lens group is a tumbler lens group, and wherein a variable-lens position of the variable-position objective lens group relative to the eyepiece lens group is controllable responsive to a movement of the magnification control; and

an aperture stop structure within the housing and lying on the optical axis between the fixed-position objective lens group and the eyepiece lens group, wherein a pupil axial position or a pupil size of the aperture stop structure is controllable responsive to the movement of the magnification control.

10. The sighting device of claim 9 , wherein the stop axial position of the mechanical aperture stop is controllable responsive to the movement of the magnification control.

11. The sighting device of claim 9 , wherein the stop size of the mechanical aperture stop is controllable responsive to the movement of the magnification control.

12. A sighting device comprising:

a fixed-position objective lens group lying on an optical axis;

an eyepiece lens group lying on the optical axis;

a variable-position tumbler lens group positioned between the fixed-position objective lens group and the eyepiece lens group;

a pivotable tumbler-lens-group support to which the tumbler lens group is mounted;

a mechanical aperture stop lying on the optical axis between the fixed-position objective lens group and the eyepiece lens group, wherein a stop position or a stop size of the mechanical aperture stop is varied according to the position of the tumbler lens group; and

a magnification control that controllably pivots the tumbler-lens-group support to controllably position the tumbler lens group to lie on the optical axis or to controllably position the tumbler lens group to lie off of the optical axis.

13. The sighting device of claim 12 , wherein the mechanical aperture stop is supported on the tumbler-lens-group support.

14. The sighting device of claim 12 , wherein the stop position of the mechanical aperture stop is varied automatically responsive to the position of the variable-position tumbler lens group.

15. The sighting device of claim 12 , further including

a housing in which the fixed-position objective lens group, the eyepiece lens group, the variable-position tumbler lens group, and the mechanical aperture stop are mounted.

16. The sighting device of claim 12 , further including

a housing in which the fixed-position objective lens group, the eyepiece lens group, the variable-position tumbler lens group, and the mechanical aperture stop are mounted, and

an attachment on the housing adapted to attach the housing to a rifle.