The resultant increment of the wave-front aberration of a lens system which is produced by a small change of the constructional parameter in the system can be represented by the equation[Equation],
where w and Δxi denote the wave-front aberration and the increment of the constructional parameter, respectively. The first term of the right-hand side of the equation represents the increment of the wavefront aberration with respect to the original reference sphere and the second term shows the increment produced by the focal shift due to the change of the constructional parameter.
The numerical result obtained from the equation showed fairly good agreement with that obtained by the actual ray tracing.
T. SUZUKI and I. UWOKI, "Differential Method for Adjusting the Wave-Front Aberrations of a Lens System," J. Opt. Soc. Am. 49, 402-402 (1959)