Fig. 2. A typical camera assembly for vertical stereophotography of the sea bottom. Two 

 cameras at the right operate in synchronism with the flash lamp at the far left. Above 

 the lamp is the sonar driver. The square flat object at the center of the framework is 

 a 12-kc pulse sonar transducer for camera-botton:i measurement. 



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Fig. 3. Example to sliow quality of special/ 11, 35-mm Hopkins lens when used under 

 water. 



