Designing a double-Gauss lens,the Hard WayDavid ShaferDavid Shafer Optical DesignFairfield,CT,06824shaferlens@sbcglobal.net#203-259-1431The Double-Gauss type ofdesign is very flexible and can givegood performance in a widevariety of combinations of fieldangle and f#speed.These daysyou can start a new design from agazillion Double-Gauss designpatents or just enter some designdata that give a drawing thatlooks like a Double-Gauss andthen computer optimize.Back in the daysbefore computers avery different styleof lens design wasnecessary.Peoplehad to use someaberration theoryand insights anddid not do morethan 2X 2 matrixoptimization-byhand.Let us see what that may have been like,but use a computer to do therequired simple calculations,as if we were doing it by hand calculations.Wewill first do a monochromatic design and then add color correction.