Le procédé

The Workshop

The distorted image is reflected in the mirror placed in its center. This reflection changes shape with the angle of vision. Unlike plane mirrors, the conical mirror, which is also a convex mirror, does not reflect all of what surrounds it.

Another particularity of the conical mirror is that what it reflects is inverted. The areas of the edge come to the center, and reciprocally the areas of the center come to the edge. The original image and the reflected image are symmetrical with respect to the circle of the base of the cone.


Above the conical anamorphosis restituted. The gray circle in the center represents the base of the cone and contains the image reflected by the cone when the viewing angle is exactly in the axis of the tip of the cone.

optical axis of the anamorphosis

On the left, the original image, on the right its inverse image, the intersections A and K, are the closest to the optical axis, they are the farthest in the distorted image

A cone anamorphosis is a precise optical system: the tip of the cone reflects the peripheral areas of the image, which are furthest from the optical axis. The optical axis of the system is the line perpendicular to the image support which passes through the tip of the mirror. This is where the viewer places himself to see the undistorted image.

Geometry of the conical anamorphosis

  • P : angle at the tip of the cone = 74
  • B : angle at the base of the cone = 53
  • d : diameter of the cone = 69 mm
  • h : height of the cone = tgBxd/2 = 45,78 mm (tg 53 = 1,327 )
  • R : radius of the distorted image = tg P x h = 159,65 mm

Conical anamorphosis geometry