Emil Busch took over the opti­cal firm in Rathenow from his uncle Eduard Dunck­er in 1845. The com­pa­ny began pro­duc­ing pho­to­graph­ic devices from 1852 and became known for high-qual­i­ty instru­ments and optics. In 1865, it intro­duced its new­ly devel­oped wide-angle lens, the Pantoscop.
From 1872, the com­pa­ny con­tin­ued as Rathenow­er Optis­che Indus­trie-Anstalt vor­mals Emil Busch A.-G.. In 1927, the major­i­ty of the shares was acquired by Carl Zeiss Jena. Busch con­tin­ued man­u­fac­tur­ing cam­eras but ceased lens pro­duc­tion. The com­pa­ny build­ings in Rathenow were destroyed at the end of World War II.