Winlens lab instructions

With the object at infinity, register the Geometric MTF, Chromatic Aberration
(COL) and Field Aberrations (FLD).
a) The effect of a filter on the quality of the image
In photography, filters are used for many different purposes. In this part of the
exercise, you will examine the effect of the filter on the quality of the image.
The exercise does not concern the actual filtering effect (color correction,
polarization etc), only the effect on the image due to refraction at the filter
surfaces. For this reason the “filter” is modelled as a simple glass plate. To make
the effect visible, use a rather thick filter: a planar parallel plate of BK7, 20mm
thick, and 50mm in diameter. Create the filter as a user defined lens with infinite
radius of curvature for both surfaces. To achieve infinite radius of curvature, set
the radius to 0. Place the “filter”
a. on the image side, immediately behind the objective
b. on the object side, immediately in front of the objective. (Use the
Insert Blank Row option on the Edit menu to make room for the filter in the
system data editor.)
Compare the Geometric MTF, Chromatic Aberration and Field Aberrations for
the three cases
o No filter
o Filter behind the objective
o Filter in front of the objective
Discuss what happens when a planar parallel component (the filter) is added to
the optical system. (Feel free to use additional characteristics for your analysis.)
Draw conclusions and make a recommendation regarding where to place the
filter.
b) The effect of object distance on the imaging performance
Most camera objectives are designed to give their best image formation for
distances of 100 focal lengths or more (i.e. image distances approximately equal
to the focal length). We will now change parameters to analyse what happens
when we use the objective for
1:1 imaging.
Remove the filter. Then do a and b below.