DEVELOPMENT OF A NEW WIDE ANGLE AMERICAN LENS
The 6-inch f/5.6 Geocon I, designed by Dr. James G. Baker, represents
the first American attempt to meet the lens requirements. Laboratory
tdsts showed significant gains in resolution and image quality. Only a
slight vignetting coat in the filter was required to correct the field illumi
nation. Distortion was 8 microns. The prototype, fabricated six years ago,
was installed in a KC-1 camera in which the shutter, designed for the
Planigon lens, limited the effective aperture to an effective f/8. Aerial
tests verified the gains in image quality over the Planigon, which were
observed in laboratory tests. Models were flat, and a definite increase
in efficiency of plotting operators was noted.
Two years ago, the second Geocon I was installed in a KC-4 camera. The
Rapidyne shutter was redesigned to accommodate the f/5. 6 aperture, vh ile
the platen, in accordance with modern requirements, was made plane within
0. 00020 u . Distortion again was less than 10 microns.
Again, aerial tests verified the resolution and image quality gains, and again,
models were flat. Color film exposed in this camera was good. Some photos
were unusual. The success of the Geocon I led to further design by Baker,
which resulted in the formula for the Geocon IV.
This formula predicts an AWAR of over 45 lines/mm on Plus X film,
distortion that is substantially zero, and illumination characteristics which
require only cos^ correction to produce an even distribution of light at the
focal plane. The first two prototypes are now being manufactured by Kollsman
Instrument Corp. for installation in the Fairchild KC-6A cameras, and initial
testing at Fairchild indicates the predictions will be met.
KC-6A CAMERA MAPPING SYSTEM
The KC-6A camera (see Figure 1) was conceived by Fairchild engineers during
the last half decade, specifically to meet the demands of modern, high speed
vehicles. These demands include a fast lens, a fast shutter, image motion
compensation of high accuracy, automatic exposure control, and synchronous
exposure of two or more cameras. All of these features, including the new
Geocon IV lens, and a device for recording verticality, are integrated into
the KC-6A. As noted by Di Carlo and Eakin, the KC-6A is one of the com
ponents of the Mapping and Survey Subsystem Geodetic AN/USQ-28.
KC-6A Camera Characteristics
Lens
6" f/5. 0 Geocon IV, radial distortion
less than 8 microns; tangential distortion
less than 8 microns