Modern Lens Design, 2nd Edition

Chapter 8Cooke Triplet Anastigmats

8.1 Airspaced Triplet Anastigmats

The Cooke triplet (Fig. 8.1) is an especially interesting design form for several reasons. It possesses just enough effective degrees of freedom to control or correct all the primary aberrations. Because of the nonlinearity of the relationships between the aberrations and the design variables, there are (theoretically) at least eight potential solutions for the primary aberrations, two or three of which may be useful.

The basic method used to flatten the Petzval field curvature in all anastigmats is the longitudinal separation of positive power from negative power. This separation may be between surfaces, between elements, or between components. Since the contribution to the ...