Astro-Kino VII D.R.P. 100mm f/1.4

Company Astro-Gesellschaft Bielicke & Co (Astro-Berlin)
Country Germany
Year of manufacture 1933-1934
Focal length 100mm
Aperture f/1.4
Optics (uncoated)
Inventor Hugh Ivan Gramatzki, based on D.R.P. pat. 535 883 or pat. 552 789
Type Special purpose 16mm projection lens
Mount diameter 80mm
BFL (Back focal distance) 52mm
Image circle at infinity
Material Optical glass, black painted brass (front ring), nickel plated brass (main body), black painted aluminium (back)
Weight 1125 g

Translation from German ad from 1935:

The special lens for ”Großraumprojektion” (large-format or large-scale projection) of “Schmalfilm” (Directly translated “narrow film”, meaning film smaller than 35mm in size).

Modern projection technology, which strives to achieve large images of the highest brilliance and brightness even with “narrow film” (film smaller than 35mm), also requires a projection lens of the highest performance. Luminous intensity alone is not the decisive factor, although the ASTRO-KINO is also at the forefront in this respect. A main requirement is to produce images of the highest brilliance, i.e. the strongest contrast between highlights and shadows. This is only possible with the aid of a lens in which internal reflection, the so-called “self-luminosity” of the lens, is reduced to a minimum.

This goal is achieved with the ASTRO-KINO. The lens has only 4 or 6 surfaces of air-glass, none of which is a hollow surface. The brilliance of the images projected with the ASTRO-KINO cannot be achieved at such light intensity by any construction with more reflecting surfaces or a hollow surface, since strong internal reflection leads to obscuring of the image. The sharpness of ASTRO-KINO lenses from the center to the edge meets even the highest demands.

The ASTRO-KINO is manufactured in the following focal lengths: 36mm, 52mm, 65mm, 85mm, 100mm and 120mm. Care must be taken that the projector is equipped with an appropriate condenser through which the luminous intensity of the ASTRO-KINO is really utilised.

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