Hi.

I am working on an optical system that should be attached to a camera (Figure 1). The system adds severe field curvature to the generated images. To fix the curvature I tried the method described in the 14th chapter of the book “Introduction to lens design with practical Zemax examples”, which gives an equation to calculate the radius of a field flattener given the material and the Petzval Radius of the system. In this case, Petzval radius = -0.7948. The field flattener radius should have a radius of -0.35mm (Considering the material to be N-SF11), which I guess is impossible to be fabricated. In addition, it would be convenient if this problem could be solved using off-the-shelf lenses so I tried simulating with the most similar lens I found from Edmund Optics, R = -4.71 mm, plano-concave (Figure 2). But the Petzval radius did not change much (New Petzval radius = -0.8467). Could I add more than one field flattener in the system near the field lenses? Does the solution from the book work for this problem? Is there another way I could tackle this problem? I appreciate it if anyone could give a hint on how to reduce the field curvature in this case.