As could be seen from the four analysis features, the performance of the singlet at this point is certianly not optimal.  A big factor in this fairly poor performance was the random selection of the location of the image plane.  Even from the Layout, it is obvious that the currently selected image plane is not at "best focus."



Even prior to optimization, we can use a tool within ZEMAX to better position the current image plane location.  The tool is known as the Quick Focus tool.  Quick Focus is a feature in ZEMAX which adjusts the thickness of the surface prior to the image plane to minimize the RMS aberrations.

Open the Quick Focus dialog by selecting Tools > Miscellaneous > Quick Focus or by pressing "Shift+Ctrl+Q" on the keyboard.  The "best focus" position which this tool will choose depends upon the criterion which is selected.  For the singlet design, we will use radial spot size with respect to the centroid.  Select Spot Size Radial and place a check next to the "Use Centroid" box.



Click "OK" to close the Quick Focus tool dialog.

Note the automatic change to the thickness of the surface prior to the image plane.  Update each of the opened analysis windows by selecting "Update" in the upper-left hand corner of each individual analysis window.  Note the fairly significant changes in performance simply due to the new selection of the image plane location.  Most importantly, the RMS and Geometrical spot sizes at the maximum field decreased by nearly a factor of 2!





Even though the design is undoubtedly better than before, there is still room for improvement.