Petzval lens
The Petzvalobjektiv is the first portrait lens (100 mm focal length) the history of photography; it was designed by Josef Maximilian Petzval in 1840 in Austria and built by Peter Wilhelm Friedrich von Voigtländer first, later also Dietzler was added as a producer.
The objective established two new features: First, it was with a maximum aperture of 1:3.6 over previous lenses comparatively bright light; compared to Daguerre's lens from 1839 Petzval design was 22 times more light, which for the first time allowed portraits with exposure times of less than one minute under favorable conditions.
On the other Petzval calculated for the first time the composition of the lenses on the basis of the laws of optics, while opticians had previously sanded lenses according to experience. For the calculations it by Archduke Louis of Austria ( supreme commander of the artillery ) were 8 artillery gunners and three corporals made available, as the artillery at that time was one of the few professions in which you undertook mathematical calculations.
The Petzvalobjektiv was produced by Voigtländer and distributed worldwide; until 1862 he produced 60,000 pieces.
One of the disadvantages of Petzval design included a strong focus drop at the edges, which was corrected by in the model developed by Hugo Adolph Steinheil Aplanat.
A launched on Kickstarter.com crowdfunding project aims to reconstruct the lens to use it to current cameras.