PMAG
Paraxial magnification. This is the ratio of the paraxial chief ray height on the paraxial image plane to the object height. Only useful for finite conjugate systems. Not valid for non-paraxial systems. Note the paraxial image plane is always used to compute PMAG, even if the optical system is defocused from the paraxial image plane.
这个运算元表示的是高斯像面的像高与物高之比，你要做物象比2：1的，只要把该运算元的目标值设为0.5即可。如果你把视场类型设定成 Object Height 会看得更清楚一些。
