This Austrian commemorative stamp was issued in 1973 to mark the Europophot Congress held in Vienna, celebrating advances in photography. The design features an early photographic lens associated with the pioneering optical work of Josef Petzval (1807–1891), a mathematician and physicist whose lens innovations greatly improved photographic clarity and speed. Rendered in detailed technical illustration against a blue background, the stamp highlights Austria’s contribution to photographic science. It is part of the popular Europa-themed technical and scientific commemoratives of the early 1970s and is sought after by collectors of photography, technology, and Europa issues.