![Polaroid SX-70 Sonar OneStep | by [jonrev]](http://live.staticflickr.com/8388/8511461960_b6c1a1d870.jpg)
Polaroid SX-70 Sonar OneStep
In 1978 Polaroid introduced sonar automatic focusing to its plastic "Pronto!" box camera, and flagship SX-70 folding SLR. The gold dish above the lens emits an inaudible sound wave that bounces back to the camera once it hits the subject, and immediately focuses the lens to the accurate distance. You could precisely-focus on blank walls and even on subjects in the dark with this camera... wish my Nikon could do that. The technology at the time was quirky, yet state-of-the-art, and was later used in the top-end 600-series cameras, the SLR-680/690, Impulse AF, and Spectra cameras.
Unfortunately, this particular camera worked erratically enough to earn the nickname "Bi-Polaroid", before it ultimately got itself stuck thinking it was in mid-cycle. I've since returned it... I never have good luck with SX-70 cameras on eBay.
Polaroid SX-70 Sonar OneStep
In 1978 Polaroid introduced sonar automatic focusing to its plastic "Pronto!" box camera, and flagship SX-70 folding SLR. The gold dish above the lens emits an inaudible sound wave that bounces back to the camera once it hits the subject, and immediately focuses the lens to the accurate distance. You could precisely-focus on blank walls and even on subjects in the dark with this camera... wish my Nikon could do that. The technology at the time was quirky, yet state-of-the-art, and was later used in the top-end 600-series cameras, the SLR-680/690, Impulse AF, and Spectra cameras.
Unfortunately, this particular camera worked erratically enough to earn the nickname "Bi-Polaroid", before it ultimately got itself stuck thinking it was in mid-cycle. I've since returned it... I never have good luck with SX-70 cameras on eBay.