390 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1936 



excellent aerial cameras. The development of these cameras has 

 been along two general lines: First, the development of cameras 

 suited to the producing of mosaic maps of a convenient scale or for 

 making oblique views; and, second, the development of a camera 

 for mapping purposes in which the coverage of a large area is 

 desirable and the recording of the detail as shown in a mosaic is 

 not necessary. These second cameras are of the multiple-lens type. 

 The development of aircraft permitting flight at higher altitudes 

 and the development of wide-angle lenses is tending to change both 

 types of cameras. The single-lens camera may require a longer 

 focal length lens to produce contact prints of a scale usable for 

 mosaics from the altitude at which the airplanes are beginning to 

 fly regularly, and in this case a larger picture should be taken to 

 reduce the flying time to a minimum. In the case of the mapping 

 cameras, the development of extremely wide-angle lenses promises 

 to give a single picture including such a wide angle of view that 

 it will cover as great an area as the usable part in the pictures taken 

 with the five-lens camera. When this point is reached the necessity 

 for a camera with more than one lens will no longer exist. 



