Portrait lens

inventor: Joseph Petzval, engineer - mathematician, university professor and inventor
time of inventon: around 1840-41

About the inventor

Joseph Petzval

He graduated as an engineer at the predecessor institution of the Budapest University of Technology and Economics. Later he also obtained BA university degree in mathematics. Between 1828 and 1835 he worked as an urban engineer of the city of Pest at the department of construction. From 1832 he was university professor at the Budapest University of Technology and Economics, and later from 1836 till 1877 he taught mathematics at the University of Vienna. He was a member of the Academy of Sciences in Vienna (1849), and an external member of the Hungarian Academy of Sciences (1873)

Beyond mathematics, his researches extended to the fields of mechanics, ballistics, optics and acoustics. He was a pioneer in photography by creating the Petzval portrait lens which served as the basis of the portrait lens system of modern photography. Beside other fantastic inventions, he also carried out experiments in optics. As a result, among others, he constructed floodlights, the predecessor of military spotlights. He also thoroughly studied lens system calculations that led to the perfection of telescopes and microscopes. Moreover, he redesigned and improved the telescope of Galilei.

The Petzval portrait lens

The Petzval portrait lens was created around 1840-1841. It was a double achromatic lens with a focal lengths of 149mm, and with high luminous intensity. It was a very complexly designed lens system that made possible crucially shorter exposure times — using exposures of only about 15 to 30 seconds compared to the previous 2-30 minutes. In fact, very few modofications have been made on it since its invention, and it is still being one of the best portrait lenses of the world. It was wide spread till the end of the 1990s, only the Tessar lenses (1902) were able to exceed its quality.

Source: Wikipedia