UMPLFN20XW.__init__

raytracing.olympus.UMPLFN20XW.__init__(self)

General microscope objective, approximately correct.

We model the objective as an ideal lens with back focal point at the entrance and front focal plane “working distance” after the last surface. In between, we propagate from one principal plane to another with the identity matrix, with the planes separated by focusToFocusLength-2*f All the elements that describe this objective will cumulate to a total distance of focusToFocusLength. However, the physical length of the objective is shorter: the focal point is outside the objective, therefore the objective has an actual length of focusToFocusLength-workingDistance. The numerical aperture is used to estimate the front aperture.