Two designing results of a complex imaging object lens and its advanced design method are described. A thin lens with less power is added near the stop location in the advanced design

which can reduce 5th negative spherical aberration and give 5th negative astigmatic(-0.1107) to match the 5th positive astigmatic given by the former design. It also gives -0.0628 negative field curve. The astigmatic and field curve are obviously improved to get a better image

Especially

the value of MTF in 1 field is 0.493 in advanced design.