The SX-70 is a folding single lens reflex Land Camera which was produced by the Polaroid Corporation from 1972-1981.
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Though Polaroid had considered a Henry Dreyfus-designed SLR for its Colorpack film, the SX-70 was the first instant SLR and the first camera to use Polaroid's new SX-70 integral print film, which developed automatically in broad daylight without the need for intervention from the photographer. The SX-70 was also notable for its elegant folding design, which allowed the camera to be compact enough to fit a man's suit-jacket pocket when collapsed.[1]
There were a variety of models beginning in 1972 with the original SX-70, though all shared the same basic design. The first model, sold in Florida in late 1972, had a plain focusing screen (the user was expected to be able to see the difference between in- and out-of focus) because Dr. Land wanted to encourage photographers to think they were looking at the subject, rather than through a viewfinder. When many users complained that focusing was difficult, especially in dim light, a split-image rangefinder prism was added. This feature is standard on all later manual focus models.
The later Sonar OneStep and SLR 680 models were equipped with a sonar autofocus system, which permitted returning to the plain focusing screen. The Sonar Onestep models were the first autofocus SLRs available to consumers. Polaroid Corporation marketed this relatively inexpensive, novel sonar technology as a set of components to hobbyists in order for them to incorporate distance sensing into other systems. The later SLR 680/690 models updated the basic design of the Sonar Onestep to more modern standards by incorporating support for newer 600 cartridges instead of SX-70 cartridges, and a built-in flash instead of the disposable Flashbar. Today they are the most evolved forms of the SX-70, and are highly sought after by Polaroid enthusiasts.
Though expensive, the SX-70 was popular in the 1970s and retains a cult following today. [2]
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 an erect image on the film and an erect aerial image for the viewfinder[3]. 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 used 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.
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.
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. [4] Polaroid later released development kits to allow the Polapulse battery to be used in non-photographic applications. [5]
Polaroid's SX-70 "Time-Zero" film was phased out of production in late 2005 to early 2006 (differing according to regional markets). Small quantities of the film may still be acquired, however at often very highly inflated prices. Thus, SX-70 users are left with three options for using new film in their cameras:
Polaroid SX-70 Blend Film
In October 2006, a brand new SX-70 film pack was licensed by Polaroid and produced at the Netherlands plant in small batches, with only word of mouth and Web to advertise it. It very cleverly used an integrated neutral-density filter and modified 600 film chemistry to yield vibrant colors, strong contrast, and high resolution. As the cartridge was made to its original SX-70 specifications, and the ND filter was placed over the opening of the film pack and not the lens, it allowed for full and normal use of all the camera's functions. Unfortunately, when Polaroid ceased production of all film, the SX-70 Blend did as well.
Polaroid 600 film
Many SX-70 owners modify their cameras to use Polaroid's more recent 600 film, although it is now discontinued. SX-70 and 600 film are not exactly the same, however, the 600 having some extra little 'nubs', so photographers must either use a playing card or dark slide from a used Polaroid film pack to help slide the 600 film into the camera or slice the nubs off the cartridge.
Another problem with using 600 film is that its speed is two stops faster than SX-70 film, causing overexposure. To address this issue, some photographers simply set the exposure dial all the way to "darken" and replace the small ND filter over the electronic eye with a similar clear filter. Polaroid itself recommends placing a 1-stop ND filter over the lens, and replacing the small ND filter over the electronic eye with a clear piece of plastic (as from a CD case). Even with these modifications, SX-70 users may find they need to set the exposure controls fully to "darken."
Perhaps the most effective way to use 600 film is to have the SX-70's exposure electronics electronically modified to accept the film's higher speed. The advantage to this type of camera modification is that the camera will expose the film correctly without the use of filters or exposure adjustments. Full exposure control is retained, and one does not have to worry about forgetting to set the exposure to "darken" each time the camera is opened. Furthermore, this type of modification allows the camera to benefit from faster exposures, as it causes the camera to function at a true ISO 640 film speed. These modifications are very difficult to perform except by experienced camera technicians.
Impossible Project
While Fujifilm still produces some of the older-style, professional 'peel-apart' films, Polaroid's Enschede, Holland film plant was the last manufacturing center for the 'integral' SX-70, 600 and Spectra films. However, in late 2008 several former employees of the Polaroid plant and Florian Kaps (the Austrian entrepreneur behind the effort) undertook the aptly named Impossible Project ( http://www.the-impossible-project.com )
They were able to take a lease on the plant and intercept the 9 integral-film assembly-machines before they were cut up and hauled off for scrap. They are currently working from scratch to create new development chemicals so that they can begin selling new versions of the 125 and 600 ASA films in 2010.
On 22 March, 2010, Yahoo News reported that the "Impossible Project" had borne results in the form of "instant film," which was reported by the Associated Press' Technology Writer Peter Svensson.
The Associated Press' article said: "A group of engineers and enthusiasts who leased an old Polaroid film factory in the Netherlands announced Monday that they had successfully reinvented instant film and will start selling packs this week."
One feature of SX-70 integral print film is its ability to be manipulated while developing, and for some days after. Because the emulsion is gelatin-based, and the Mylar covering does not allow water vapor to readily pass, the emulsion stays soft for several days, allowing artists to press and manipulate the emulsion to produce effects somewhat like impressionist paintings. An example of this technique was used on the cover of Peter Gabriel's third album, Peter Gabriel.
The 500, 600, and Spectra/Image materials do not use a gelatin-based emulsion, and cannot be manipulated this way.
Manipulation of the photograph is best done about two minutes after the picture has fully developed. It will stay soft and workable for about 5–15 minutes. Some colors will be more difficult to work on (dark green), whereas others are workable for a long time (red). If the photo is on a warm surface or slightly warmed in an oven, image manipulation is made easier.