Koristka was an Italian optical company, based in Milano. It was founded in the 1880s and the full name was Fratelli Koristka. They made binoculars, microscopes, and some camera lenses. Among them is a Victor 55/3.5 in Leica screw mount Francesco Koristka, of Polish origin (Silesian to be precise), after having worked in Vienna and he was aide-de-camp Salmoiraghi, stood on his own and founded in Milan in 1881 (everywhere but in 1880 is an old advertising of Onward I found clearly written: f. Koristka S.A. (Casa founded in 1881 *) a firm, Mechanical Optics f. Onward, which became the most important in Italy for the construction of microscopes and one of the few Italian precision industries that exported both in Europe and America. Thanks to his relationship with Ernst Abbe (1840 – 1905), Onward was given the opportunity to build microscopes and photographic lenses using the Zeiss patents in the same way that worked the Krauss in Paris, but also builds from the original project objectives as telephoto Negri-Onward, and later the Ars, Sideran, Sagittal, Meridian and the telephoto Proximar. In 1929 the Koristka was absorbed by the Officine Galileo (at least a part 'cause it seems that the company ceases the activity entirely in 1968, when some employees found the COMP, with poor production) of Florence who had need to enhance their potential in the field of optical glass production in the aftermath of World War I and the subsequent need to produce optical Itaila which until then had been entirely imported from abroadfor the Gamma (Italian Leica copy)Argo Binoculars 8x30 Fratelli Koristka Milano Italy makers Unknown date , maybe 1920's? .One of the few binocular builders in Italy! Heavy white metal with brass covers. 26 oz. or 216.84g Porro prism almost circular exit pupil 3mm in 15mm wide glass focusing eyepieces of indiviual design. Precesion machining image quality good for 91 years old!