After completing his studies Steinheil moved to Munich, where he became professor of physics and mathematics at the University of Munich in 1832. Pursuing research into telescopes and optical calculations, he constructed a photographic camera in 1839 and began photographic experiments with fellow professor Franz von Kobell. After Daguerre's discovery, Steinheil built another camera and began making the first daguerreotypes in Germany. In 1839 he also made a miniature camera to handle 8x 11mm daguerreotype plates. The physicist then established a workshop in Munich, where he constructed a telegraph apparatus used in a telegraph system he installed in Austria in 1849-50 and in Switzerland in 1851. In 1855, along with his son, he established the Optical Workshop of C. A. v. Steinheil in Munich, which later became C. A. Sternhell Söhne. For ten years the business chiefly handled optics for astronomy, but in 1865 the Steinheils obtained a patent for a distortion-free symmetrical Periskop lens for photography. In 1866, the year he transferred the company's ownership to his sons, he designed a miniature camera with a plate-changing device.