Calculational technique for an iris with an elliptical aperture

摘要

This paper proposes an analytical calculational technique for a uniform iris with an aperture of elliptical shape. The purpose of the device is to regulate the depth of sharply imaged space. Anamorphic objectives are not suitable for this, because the depth of field is different in the vertical and horizontal directions. The technique is based on an original theory of envelopes, which in this case considers the working face of the leaf of the iris that coincides with a curve that envelops a family of ellipses that open out to a certain angle relative to the fixed pin of the iris leaf.