SX-70

The SX-70 is a folding single lens reflex Land Camera which was produced by the Polaroid Corporation from 1972-1977.

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 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.

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, Dr. Land was forced to include a split-image rangefinder prism of the kind used on 35mm SLR focusing screens. This feature is standard on the SX-70 Model 2.

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 Flash bar. Today they are the most evolved forms of the SX-70, and are highly sought after by Polaroid enthusiastsFact|date=August 2008.

Though expensive, the SX-70 was popular in the 1970s and retains a cult following todayFact|date=August 2008.

Design features

The SX-70 included many sophisticated design elements. A collapsible SLR required a complex light path, with many mirrors (including one Fresnel reflector) of unusual shapes and at odd angles. Many mechanical parts were precision plastic moldings. The body was glass-filled polysulfone plastic (later models would switch to the less-expensive and more-easily cracked ABS) plated with chrome and nickel. This plating looks and feels so much like solid metal that some users still insist the camera is solid stainless steel. The film pack contained a flat battery to power the camera electronics 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 of stainless steel-look plastic and leather or synthetic surfaces. Most of the same technology was later sold in rigid plastic versions.

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 replaced in the early 1980's by the improved "Time-Zero" SX-70 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 the "Face Place" photo booth, where a battery is not needed.Time Zero was the film manufactured up until 2005, some last run film packs were marked only as SX-70, they were in fact Time Zero and not the original 1972 film.

Film issues

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 two options for using new film in their cameras:

Polaroid SX-70 Blend Film

In October 2006, a brand new SX-70 film was introduced. It uses an internal neutral-density filter and modified chemistry to yield vibrant colors, strong contrast, and high resolution. This professional-grade film is made by a private company in Austria. As the cartridge is made to its original specifications, and the ND filter is placed over the film and not the lens, it allows for full and normal use of all the camera's functions.

Polaroid 600 film

Many SX-70 owners modify their cameras to use Polaroid's more recent 600 film, although it will soon be 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 case 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, and the 600 cartridge will fit without having to trim off the tabs. 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, and are beyond the scope of this article, however there is at least one camera technician in California who offers this service.

Image manipulation

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.

Manipulate of the photograph is best done about two minutes after the polaroid 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 polaroid is on a warm surface image manipulation is made easier.

ee also

*Instant camera
*Edwin H. Land
*James Gilbert Baker
*Polaroid Corporation
*Instant film

References

External links

* Polaroid SX-70 series camera manual in PDF format on [http://www.polaroid.com/media/com/pdfs/userguides/photographic/sx70_ug_v2_m56577569830476875.pdf Polaroid.com]
* [http://www.polaroid.com/sx70/ Polaroid SX-70/Time-Zero Film Important Notice 2006]
* [http://www.polaroid.com/ifilm/en/index.html Notification of Polaroid Instant Film Availability 2008]
* Additional information about [http://www.sx70blend.com/ SX-70 blend] from unsaleable.com.
* Polaroid SX-70 page on [http://www.camerapedia.org/wiki/Polaroid_SX-70 Camerapedia.org]
* [http://www.chemie.unibas.ch/~holder/SX70.html The Hacker's Guide To the SX-70]
* [http://www.whale.tw Taiwan Instant Photography Club-台灣拍立得攝影網]
* [http://www.pola-art.de SX-70 Polaroid Art Gallery]
* [http://www.pola-art.de/technique Image manipulation]
* [http://www.raumzeitfilter.de/polaroi_e.htm The Polapola-Project]
* [http://www.polanoid.net/ Polanoid] A public collection of more than 100,000 Polaroids