(241) 
18 
DEVELOPMENTS IN PHOTOGRAMMETRIC EQUIPMENT 
by 
J. E. Odle, Williamson Manufacturing Company, Limited, Londen, England. 
Progress in the Williamson organization since the last congress has been 
steady and continuous. The Multiplex has been steadily improving, resulting in 
an instrument of considerable accuracy and increased range. 
A particular feature has been the development and application of rigid 
laboratory controls for optical systems, resulting in increasing freedom from 
the problems of distortion and asymmetric lens error. Users are encouraged to 
have their cameras recalibrated seasonally to ensure maintenance of high stand 
ards. Close liaison with Service and Government Research Organizations has 
resulted in the smooth application of specifications and standards, acceptable to 
constructors and users alike. The development of new testing instruments and 
techniques has enabled these high standards to be applied on a production line 
basis. The position of new instruments and development is briefly summarised. 
New Wide Angle Multiplex. The use of twin aspheric condensers has virtu 
ally doubled the illumination of the multiplex projector. Surface coating of all 
air to glass surfaces has reduced glare and improved resolution. The reduction 
in lamphouse height has improved the tangent screw movements. BX and BY 
motions have been slowed down. The tracing table has been redesigned to give 
direct optical projection from interchangeable glass scales, a wide range of 
which are now available. The Multiplex is being increasingly used for bridging, 
the detail plotting being undertaken in instruments with a larger viewing scale. 
New Survey Camera. The Eagle IX Camera has been redesigned and 
adopted as an R.A.F. type, using lenses of 6", 12" and 24" focal length. Distor 
tion free 6" and 12" lenses are available with side entry between lens shutters. 
The resolution of all these lenses has been improved. 
New Rectifying Enlarger. A rectifying enlarger with a magnification range 
of 4—1 and a 2—1 has been developed for 9"X9" negatives. Manufactured and 
designed to Government specifications of performance, weight and height, this 
instrument fulfills the theoretical requirements of complete rectification. A 
special lens of 5.2" focal length was developed by Ross for this project. 
Tilt Indicator. An experimental indicator has been constructed for use in 
survey cameras, the first tests of which are encouraging. 
Image Compensation. A swinging camera mount for image compensation 
has been developed and tested. The method is satisfactory and is being further 
developed for military purposes. 
Large Scale Plotter. A careful study has been made of the problems inherent 
in the use of Multiplex for large scale plotting. The limiting of flight altitude 
for large scale plans had led us to desingn an instrument employing 9" X 9" con 
tact diapositives. Further information about this instrument will be available 
later.