Lens sensitivity to aberration: scaling rules

Abstract

. We show that aberration sensitivities are independent of lens scaling when the perturbation amount is kept the same. This behavior is in agreement with the results of actual calculation. Further, we point out that aberration sensitivities scale in the same way as aberration scale as a function of the lens field of view and aperture.

Unusual astigmatism encountered in an optical assembly having a moderate field of view

“…The wavefront produced by an optical system can be expressed by a mathematical function dependent on exit pupil height (ρ ), image height (H), and an azimuthally varying (cos (θ)) terms which varies in the exit pupil 4 as shown in Table 3. In this format spherical aberration varies as ρ 4 and is independent of H and cos (θ) terms, coma varies as ρ 3 and is linear in H and cos(θ), and astigmatism varies as ρ 2 and varies with H 2 and cos 2 (θ). A different way to think about the cause of coma when a lens is decentered is that the spherical aberration that is associated with the decentered lens has its spherical aberration sheared with respect to another lens, usually nearby.…”

“…If they shear in a fashion to correct the axial coma, then what would remain is astigmatism. Since field coma varies as ρ 3 , differentiating with respect to ρ obtains ρ 2 , which is the power of ρ associated with astigmatism. Moreover, field coma varies with H, so the resulting variation in astigmatism would be also vary with H and thus be linear, as predicted by Sasian and Thompson.…”

“…Thompson 1 authored an initial paper that discusses this astigmatism as advanced aberration theory. Sasian 2,3 has authored recent papers that discusses the additional mathematical derivations of what he has termed linear astigmatism. It appears that this is the astigmatism that has been observed in the current assembly.…”