Design features
The SX-70 included many sophisticated design elements. A collapsible SLR required a complex light path for the viewfinder, with three mirrors (including one Fresnel reflector) of unusual, aspheric shapes set at odd angles to create erect images both in the viewfinder and on the film. Many mechanical parts were precision plastic moldings. The body was glass-filled polysulfone, a very rigid plastic which could be plated with genuine copper-nickel-chromium. Models 2 & 3 would switch to the less-expensive and more-easily cracked ABS in either Ebony or Ivory color. The film pack contained a flat, 6-volt "PolaPulse" battery to power the camera electronics, drive motor and flash. The original flash system, a disposable "Flash Bar" of 10 bulbs from General Electric, used logic circuits to detect and fire the next unused flash.
Models
The original SX-70 was a high-end consumer market camera, with a folding body finished in brushed chrome and genuine leather panels. It could utilize a whole array of accessories, such as a close-up lens (1:1 @ 5 inches), electrical remote shutter release, tripod mount and an Ever-Ready carrying case that hung from the neck and unfolded in concert with the camera. Most of the same technology was later sold in rigid plastic fixed-focus versions, Pronto, Presto and OneStep. In its heyday, the OneStep's simplicity, bargain price and use of the same instant film made it the #1 selling camera in the USA.
Film history
Polaroid SX-70 film was introduced to the market in 1972, and was a market success despite some problems with the batteries on early film packs. The original SX-70 film was improved once in the mid-'70s (New Improved Faster Developing!) and replaced in 1980 by the further advanced "SX-70 Time-Zero Supercolor" product, in which the layers in the film pack were altered to allow a much faster development time (hence the "time zero"). It also had richer, brighter colors than the original 1972 product. There were also professional market varieties of the SX-70 film including 778 (Time Zero equivalent) and the similar 708, Time Zero film without a battery, intended for use in applications such as the "Face Place" photo booth and professional or laboratory film-backs, where a battery is not needed. Time Zero was the film manufactured up until 2005, though overseas-market and some last run film packs were marked only as SX-70.
A feature of the SX-70 film packs was a built-in battery to power the camera motors and exposure control, ensuring that the battery would never be exhausted as long as film was in the camera. The "Polapulse" battery was configured as a 6 volt thin flat battery, and used zinc-chloride chemistry to provide for the high pulse demand of the camera motors. Polaroid later released development kits to allow the Polapulse battery to be used in non-photographic applications.