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6* Itek Corporation, Lexington, Mass. USA 
Sinusoidal variable-area targets were employed. A set 
of different fixed spatial frequency targets on a rotating 
drum were located in the image plane of the lens. Measure 
ments of the separate sine and cosine transmission components 
are made and computation of the OTF made (the root of the sum 
of the square of these two components)• The collimator had 
a 400 cm focal length. The estimated accuracy was ± of the 
MTF at zero spatial frequnecy. 
7« Optics Technology Inc., Palo Alto, California, USA 
Sinusoidal variable-density targets having a continuously 
variable spatial frequency were used. These were located at 
the image plane and continuously scanned the line image to 
yield the MTF directly. The estimated accuracy was - 1% of the 
MTF at zero spatial frequency. 
8. National Bureau of Stardards, Washington, D. C., USA 
A set of sinusoidal variable density targets, each of fixed 
spatial frequency, were arranged on a linear slide. These were 
illuminated and located in the object plane, and laterally dis 
placed to perform the scanning operation. The collimator focal 
length was 180 cm. The estimated accuracy was about * 2% of the 
MTF at zero spatial frequency* 
NOTE: Detailed descriptions of these methods, in most 
cases, will be found in the references given below. 
References to the Test Methods Employed 
1. FTB - Rosenbruch, K. J., and Rosenhauer K., Optik, 21, 
652, (1964) Messung der Optischen Ubertragungs-funktion 
Nach Amplitude und Phase mit Halbautomatischen Analysator. 
See Also: Zeitschrift f. Instrumentonkunde, 67t 638 (1938) 
2. RAE - Naish, J. M., and Marchant A. C., RAE Technical Note 
PH493» January (1938) Measurement of the Response Function 
of an Optical System* 
(A modified technique is now in use)• 
• BBC - Sproson, W. N. and Hacking, K., BBC Engr. Monograph 
No. 50» Sept. (1963) New Methods of Lens Testing and 
Measurement. 
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