Joseph Petzval (January 6, 1807 - September 19, 1891) was a German-Hungarian mathematician, inventor, and physicist. He is considered to be one of the main founders of geometrical optics, modern photography and cinematography. Among his inventions and works are the Petzval portrait lens, opera glasses, lens system calculations that led to the perfection of a telescope and microscope (1843), computations for efficient binoculars, and construction of new floodlights (1847). He is also credited with the discovery of the Laplace transform, and some think it should be called the Petzval transformation. Later he concerned himself with acoustics and was particularly concerned with string oscillations, differential equations of the string oscillations, and the mathematical theory of musical instruments. He became a member of the Hungarian Academy of Sciences in 1873. In 1877, he stopped lecturing, withdrew to a monastery, and became a hermit.