Bernotar Carl Zeiss Jena DDR M49P + polarizing filter box.

In very good used condition, no scratches on the lens, please note the pictures.

History of the polarizing filter, source wikipedia:

Some scientists assume that already seafaring Vikings a polarizing filter ( sun stone) used to determine the direction of the sun on cloudy sky.

Already in the 19th Century , so in the early days of photography , it has been recognized that annoying glossy reflections , such as the inclusion of oil paintings or objects located behind glass , could be suppressed by the use of polarizing media.

Lack of alternatives, we initially used either nicols or tourmaline crystals .

The discovery of the strong polarizing effect of artificially produced crystals of sulphate of iodo- quinine ( " herapathite ") by the English physician William Bird Herapath ( 1820-1868 ) in 1851 led to the small size of more than 1 cm ² of the resulting crystals first no practical application. Only in 1926 succeeded A. rooms in Paris to produce more usable for optical purposes crystal flat leaves of 2-3 cm.

Ferdinand Bernauer succeeded in 1935 to produce large , usable also for photographic purposes large , but thick only a fraction of a millimeter monocrystalline surface filter from sulphate of quinine. For practical application, these crystals were mounted between two glass plates. The Carl Zeiss company took over the production , initially to commemorate Herapath under the name herapathite filter , but then as early as 1936 under the name Bernotar .

In contrast to this Einkristallfilter was the almost the same time together with the company Kodak developed by Edwin Herbert Land Lots crystal filter ( " Polaroid filter") . In this a large number of tiny rectified Herapathitkristallnadeln are embedded in a colloid.

Beginning in 1939, eventually also still large dichroistische film cellulose filter dye complexes ( " Celli Polar" ) were available.