[ATM] f/4 Design

[Richard F.L.R. Snashall]

In honor of this year's winter solstice split in the US between
the 21st and the 22nd (maybe I'll celebrate both days!).  This
one is 75 mm f/4:

    http://users.rcn.com/rflrs/Ptz10-55x.atm   ATMOS input file
    http://users.rcn.com/rflrs/Ptz10-55x.len   OSLO input file
    http://users.rcn.com/rflrs/Ptz10-55x.txt   TEXT prescription
    http://users.rcn.com/rflrs/Ptz10-55x.zmx   ZEMAX input file

Not large, but the field (8 degrees -- 42 mm) is flat.  All lenses
are plano or iso with common glass types.  It is relatively good
zonal correction and low lateral color.  Visual Strehl ends up
being from 0.6238 to 0.1625.