The Petzval objective, or Petzval lens, is the first photographic portrait objective lens (with a 160 mm focal length) in the history of photography.[1] It was developed by the Slovak mathematics professor Joseph Petzval in 1840 in Vienna,[2] with technical advice provided by Peter Wilhelm Friedrich von Voigtländer . The Voigtländer company went on to build the first Petzval lens in 1840 on behalf of Petzval, whereupon it became known throughout Europe.[2] Later, the optical instruments maker Carl Dietzler in Vienna also produced the Petzval lens.[2]