Optische Werke Rüdersdorf A.G. was a German optical company based in Berlin during the 1920s. It was originally founded in Bremen around 1919 – 1920 and used the trademark Rüo / Rüo-Optik for its lenses. In 1922, the company was reorganized under the name Optische Werke Rüdersdorf A.G., Bremen, and shortly thereafter relocated to Berlin, adopting the same name. The company became publicly listed in February 1926 but ceased production in 1932.
Very little information survives about this company and its lenses. Two known patents DE382193 (1922) and DE461083 (1925) were filed under the name Hugo Hahn.
The Rüo Kino 5cm f/2.5 lens features a triplet design consisting of three elements in three groups. This design offers good image quality at a relatively low production cost, as it eliminates the need for cemented elements. However, the increase in internal air-to-glass surfaces leads to higher internal reflections, which can cause a bloom effect when shooting at wide apertures. Additionally, aberration distortion becomes noticeable at apertures faster than f/3.5.
The lens produces a warm color tone and delivers rich, saturated colors when shooting at around -1/3 EV exposure compensation.
