|
Stereo Realist
The Stereo Realist is a stereo camera that was manufactured by the David White Company from 1947 to 1971. It was the most popular 35 mm stereo camera ever manufactured ''Amazing 3-D'', pages 32 and 51. and started the era of popular stereo photography of the mid 20th century. History Seton Rochwite was a camera hobbyist who began designing and building his own stereo cameras in 1929. In 1938, he began working on a version suitable for commercial manufacture. The first prototype was ready in 1940. He brought it to the David White Company of Milwaukee who, interested in the design, hired him in 1943. The company began advertising the "Stereo Realist" in photography magazines in 1945, although it was not produced until late 1947. ''Amazing 3-D''. The David White Company had great success marketing the Stereo Realist system to the public. In addition to the stereo cameras there were special slide viewers, projectors, film cutters, slide mounting aids, cases, and other accessor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stereo Realist
The Stereo Realist is a stereo camera that was manufactured by the David White Company from 1947 to 1971. It was the most popular 35 mm stereo camera ever manufactured ''Amazing 3-D'', pages 32 and 51. and started the era of popular stereo photography of the mid 20th century. History Seton Rochwite was a camera hobbyist who began designing and building his own stereo cameras in 1929. In 1938, he began working on a version suitable for commercial manufacture. The first prototype was ready in 1940. He brought it to the David White Company of Milwaukee who, interested in the design, hired him in 1943. The company began advertising the "Stereo Realist" in photography magazines in 1945, although it was not produced until late 1947. ''Amazing 3-D''. The David White Company had great success marketing the Stereo Realist system to the public. In addition to the stereo cameras there were special slide viewers, projectors, film cutters, slide mounting aids, cases, and other accessor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Detent
A detent is a mechanical or magnetic means to resist or arrest the movement of a mechanical device. Such a device can be anything ranging from a simple metal pin to a machine. The term is also used for the method involved. Magnetic detents are most often used to divide a shaft rotation into discrete increments. Magnetic detents are inherent in some types of electric motors, most often stepper motors. Mechanics Arresting movement Ratchet and pawl The ratchet-and-pawl design arrests movements by employing a small gravity- or spring-actuated lever paired with a notched wheel. The lever is mounted on a pivot point in proximity to the wheel. The vertical angle of the sides of the notches that face the direction that rotation is desired is generally very acute (45 degrees or less), so that as the wheel rotates in that direction, the end of the lever is easily lifted or pushed out and over the top of a notch. Following this, the lever drops into the next notch and the next et cet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kangaroo Leather
Kangaroo leather is a strong light weight leather derived from the hide of the kangaroo. Kangaroos are harvested. Both the meat and the hides are sold. Although hunting most species of macropod is prohibited, a small number of the large-sized species with high populations can be hunted by commercial hunters. This policy has been criticised by some wildlife activists. Applications The leather is used in a wide variety of shoes. The unique structure of kangaroo leather allows it to be cut down to be very thin, but still retain strength. Kangaroo leather is also popular in the manufacture of motorbike leathers and is used for many other applications such as car upholstery, military, football, and soccer boots, and fashion accessories. Kangaroo leather is the material of choice for making whips, as the strips can be cut thin to keep the whip flexible, without sacrificing durability. Properties Studies conducted by the Australian Commonwealth Scientific and Industrial Research ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rare-earth Mineral
A rare-earth mineral contains one or more rare-earth elements as major metal constituents. Rare-earth minerals are usually found in association with alkaline to peralkaline igneous complexes, in pegmatites associated with alkaline magmas and in or associated with carbonatite intrusives. Perovskite mineral phases are common hosts to rare-earth elements within the alkaline complexes. Mantle-derived carbonate melts are also carriers of the rare earths. Hydrothermal deposits associated with alkaline magmatism contain a variety of rare-earth minerals. The following includes the relatively common hydrothermal rare-earth minerals and minerals that often contain significant rare-earth substitution: *Aeschynite-( Y or Ce) *allanite *apatite * bastnäsite * britholite * brockite * cerite *Dollaseite-(Ce) *fluocerite * fluorite * gadolinite * monazite *parisite-( Ce or La) * stillwellite * synchysite *titanite * wakefieldite *xenotime *zircon Zircon () is a mineral belongin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vignetting
In photography and optics, vignetting is a reduction of an image's brightness or saturation toward the periphery compared to the image center. The word '' vignette'', from the same root as ''vine'', originally referred to a decorative border in a book. Later, the word came to be used for a photographic portrait that is clear at the center and fades off toward the edges. A similar effect is visible in photographs of projected images or videos off a projection screen, resulting in a so-called "hotspot" effect. Vignetting is often an unintended and undesired effect caused by camera settings or lens limitations. However, it is sometimes deliberately introduced for creative effect, such as to draw attention to the center of the frame. A photographer may deliberately choose a lens that is known to produce vignetting to obtain the effect, or it may be introduced with the use of special filters or post-processing procedures. When using superzoom lenses, vignetting may occur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New Old Stock
New old stock (NOS), or old stock for short, refers to aged stock of merchandise that was never sold to a customer and still new in original packaging. Such merchandise may not be manufactured anymore, and the new old stock may represent the only current source of a particular item. retrieved on 2008-10-20. There is no consensus on how old a product must be to be NOS, and some people reserve an NOS label only for products that are actually discontinued. Although not an officially recognized accounting term, it is in common use in the and industries. For example, owners of classic, vintage, and antique vehicles s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
