In 1866 Andersen started to work as a joiner and mechanic out of his own workshop in Nellerød. He constructed his first camera in 1866, partly inspired by L.G. Kleffel's "Fuldstændig Veiledning i praktisk Fotograf" (Danish edition, 1865). His most important technical invention was an improvement of the "collodion wet plate process" which enabled the photographic material to be coated, sensitized, exposed and developed inside the camera. In 1876-77, he was granted a patent of a light camera which eliminated the need for a portable darkroom for use in the field. He entered into a collaboration with photographer Peter L. Petersen (after 1901: Elfelt), who was in 1883 granted an exclusive right to sell Andersen's cameras. Andersen manufactured cameras and other photographic equipment such as stereoscopes as well as microscopes and levels. His creations were represented at the Nordic Exhibition of 1888. He was often neglected or cheated by manufacturers.