Are there questions pertaining to Mr 
Maruyasu's presentation? 
a real step forward in the advancement of the aerial photographic art 
at this time, since the resolution criterion provided a readily under- 
stood means for evaluating improvements. 
This very virtue now haunts us. 
Resolution seems to be so understandable, that everyone is in- 
clined to rationalize its use as a fundamental quality parameter. In the 
effort to push for systems of higher resolution Sight has been lost of 
the fact that what is really wanted is the capability of recognizing 
smaller detail on the ground. 
Paradoxically, the idea of resolution, which in the past has been 
a major factor in advancing the state-of-the-art in aerial photography, 
has more recently been inadvertently inhibiting its progress. To under- 
stand this requires first an examination of the image forming character- 
istics of a lens-film system which for the purpose of this discussion 
may be done in a very elementary way. 
LENSES 
Illustratively indicated'in' Figure 7 is the imaging of a distance 
point source of light at a camera focal plane. Consider now the en- 
  
  
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LIGHT INTENSITY 
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p ^- 
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VL 
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Ds 
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LINEAR DIMENSION ON FOCAL PLANE 
  
  
  
  
  
  
PHOTOGRAPHIC IMAGING OF A POINT 
FIGURE 7 FIGURE 8 
circled region of the focal plane and moreover consider this region as 
tremendously enlarged and graphically plotted as light intensity versus 
distance across the focal plane. Such a graphic plot is shown in Fig- 
ure 8. Note that the point source is not imaged as a point, but that the 
light is spread out due to the imaging characteristics of the lens 
film system. 
answer your question? 
PHOTOGRAPHIC INTERPRETABILITY 9 
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acteristic of the particular emulsion. Does this 
  
  
  
  
  
  
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