The Polaroid SX-70 Sonar OneStep features a 4-element 116mm glass lens, manual or autofocus capabilities, with a minimum focal length of 10.4 inches, electronic shutter, programmed automatic exposure and a socket for flashbars or electronic flashes. Another nice feature is a socket for an electrically-actuated remote shutter release.
The SX-70 Sonar OneStep utilized a new and very advanced sonar technology. When the shutter button is pressed halfway, a series of ultrasonic chirps is emitted from an electrostatic transducer located under a plate over the lens. These chirps travel to the subject and bounce back to the camera’s receiver, alerting the camera to the subject’s distance, and the lens is turned on a motor to focus accordingly.