Anamorphic objective lens
An anamorphic objective lens comprising, along an optical axis and in order from an object space to an image space: at least a negative (−) spherical first lens group; an anamorphic second lens group and a positive (+) spherical third lens group wherein an aperture stop is located before, after or preferably within the spherical third lens group such that the anamorphic objective lens creates a traditional elliptical bokeh of out of focus objects. Both spherical lens groups contain spherical refractive optical surfaces and the anamorphic lens group contains cylindrical and plano optical surfaces with at least one cylindrical surface oriented at substantially 90 degrees about at least one other cylindrical surface. The negative spherical first lens group may provide focusing.
1. An anamorphic objective lens comprising along an optical axis and in order from an object space to an image space: a negative (−) spherical power first lens group; an anamorphic second lens group comprising at least one lens element having a non-rotationally symmetric surface shape about the optical axis; a positive (+) spherical power third lens group, and an aperture stop; whereby the anamorphic objective lens squeezes the horizontal field of view by substantially two times as compared to the vertical field of view to creates a traditional oval or elliptical bokeh of out of focus objects, the elliptical bokeh shape having a ratio of major to minor axis dimensions of substantially two to one of out of focus objects substantially centered in the field of view.
2. An anamorphic objective lens comprising along an optical axis and in order from an object space to an image space: a negative (−) spherical power first lens group; an anamorphic second lens group comprising at least one lens element having a non-rotationally symmetric surface shape about the optical axis; a positive (+) spherical power third lens group, and an aperture stop; whereby the anamorphic objective lens squeezes the horizontal field of view by substantially two times as compared to the vertical field of view to create depths of field centered within the field of view in the horizontal and vertical azimuths having a ratio of substantially two to one.
3. An anamorphic objective lens comprising along an optical axis and in order from an object space to an image space: a negative (−) spherical power first lens group; an anamorphic second lens group comprising at least one lens element having a non-rotationally symmetric surface shape about the optical axis; a positive (+) spherical power third lens group, and an aperture stop; wherein the at least one lens element having a non-rotationally symmetrical surface shape having at least two directions of surface shape.
4. The anamorphic objective lens of claim 3 , wherein said at least two directions of surface shape are perpendicular.
5. The anamorphic objective lens of any of claim 1 , 2 or 3 , wherein said negative (−) power spherical first lens group contains at least one axially movable lens element to provide focusing.
6. The anamorphic objective lens of any of claims 1 , 2 or 3 , wherein said anamorphic second lens group, has focal lengths in the X and Y directions which differ by a ratio of about two times.
7. The anamorphic objective lens of any of claim 1 , 2 or 3 , having a focal length within the range of from 25 mm to 135 mm.
8. The anamorphic objective lens of claim 7 , wherein said glass of said lens elements varies in refractive characteristic to provide low residual chromatic aberration in image space.
9. The anamorphic objective lens of any of claims 1 , 2 or 3 creates a medium fast full aperture moderately wide angle field of view.
10. The anamorphic objective lens of any of claims 1 , 2 or 3 , wherein said lens groups are fabricated of lens elements made of glass.
11. The anamorphic objective lens of any of claims 1 , 2 or 3 which has an aperture of f/2.4 and transmits radiation over a waveband of 455 -656 nm to form an image in image space.
12. The anamorphic objective lens of any of claim 1 , 2 or 3 , wherein said anamorphic second lens group comprises five cylindrically surfaced lens elements with four Y cylinders, three X cylinders and three plano surface shapes.
13. The anamorphic objective lens of any of claim 1 , 2 or 3 , wherein, said spherical power first lens group comprises two lens elements, one of which is axially moveable relative to the other.
14. The anamorphic objective lens of any of claims 1 , 2 or 3 , wherein said spherical power third lens group comprises seven lens elements.
15. The anamorphic objective Jens of any of claims 1 , 2 or 3 , wherein at least one vignetting field stop aperture is located before said positive (+) power third lens group.
16. The anamorphic objective lens of any of claims 1 , 2 or 3 , wherein at least one vignetting field stop aperture is located after said anamorphic second lens group.
17. The anamorphic objective lens of any of claim 1 , 2 or 3 , wherein at least two vignetting field stop apertures within said anamorphic objective lens.