Petzval Portrait objective Jose Sasian College of Optical Sciences University of Arizona https://en.wikipedia.org/wiki Announcement of the invention of the Daguerreotype by Arago at the meeting of the French Academy of Sciences and Arts Louis‐Jacques‐Mandé Dominique François Arago Daguerre August 19th 1939 Prof. Andreas Ettingshausen, 1796–1878 https://en.wikipedia.org/wiki/Andreas_von_Ettingshausen https://en.wikipedia.org/wiki Daguerre’s camera and the achromatic landscape lens ½ hour to take a picture: F/16 “It is known that the objectives used by Daguerre were achromatic plane‐convex‐lenses. Their plane side was turned toward the object, the convex side towards the image. They have an opening of 3 zoll, but this opening is reduced to 1 zoll by a diaphragm placed before at a distance of 3 zoll from the lenses.” J. Petzval https://en.wikipedia.org/wiki Prof. Ettingshausen asked Joseph Petzval to explore the shape of the lenses Prof. Andreas Ettingshausen Vienna University, 19th century “It was in the year 1839, when the wonderful invention by Daguerre was made public, and incited the general interest to such a high degree. At that time I was first made aware of the strange shape of Young Joseph Petzval the objectives used in Daguerre’s camera obscura by my dear friend 1807‐1891 and colleague Professor von Ettingshausen. I was asked to explore the reason for this shape.” J. Petzval https://en.wikipedia.org/wiki Petzval Portrait Lens “Greater illumination, one of the desired improvements, can only be obtained in two ways – by enlarging the aperture and by diminishing the focal length, both which, however, will result from employing two converging lenses, instead of one. These lenses must of course be achromats; and by theory, in order that a good image may be produced, they must be separated from each other by a distance no less than one third of the focal length of the lens near the object.” Petzval 1857. F/3.6 40 seconds to take a picture Joseph Eder’s remark “The commercial success of the Petzval portrait lens was immediate and extraordinary, and that it spread with unexpected rapidity.” https://en.wikipedia.org/wiki/Josef_Maria_Eder Petzval lens imaging Beatrice Cenci with Kate Keown Photograph by as the model, Wikipedia Julia Margaret Cameron 1868 Wikipedia Bokeh is the aesthetic quality of the lack of sharp focusing in the images produced by a lens, especially In the outer parts of the field. https://en.wikipedia.org/wiki The question • How did Petzval design his famous portrait lens • Did he use real ray tracing? • Did he use third‐order aberration coefficients? • Did he have help? • Petzval did not leave a record about how he did the designs • The announcement of the Daguerrotype was on August 1939 • Petzval had his designed done by May 1840 Prof. Ettingshausen suggests to P. W. Voigtländer to talk to Petzval Prof. Andreas Ettingshausen, P. W. F. Voigtländer, lens manufacturer in Vienna https://en.wikipedia.org/wiki P. W. Voigtländer meets Petzval and provides glass indices of refraction and dispersion values Young Joseph Petzval P. W. F. Voigtländer https://en.wikipedia.org/wiki Petzval produces by May of 1840 two objective designs (actually four) For portraits For “views” (landscapes) https://en.wikipedia.org/wiki First camera with the Petzval Portrait objective • Voigtländer manufactured the objectives • The portrait objective working at F/3.67 allowed taking photographs in seconds (~40) making portrait photography a practical reality. • Anton Martin took photographs to evaluate the lens Anton Martin https://en.wikipedia.org/wiki Petzval’s Original Prescription The prescription has two sets of data for landscapes and for portraits. Written in ink and in pencil. NATIONAL BANK OF SLOVAKIA P. W. F. Voigtländer notarized copy Akademiker Prof. Dr. Petzval, beleuchtet von Voigtländer, NATIONAL BANK OF SLOVAKIA Drud und Berlag von Friedrich Biemeg und Gobn, Braunschweig 1859. The two sets of prescriptions Given in linien, zoll, and zoll and linien old German units In ink and in pencil No indices of refraction, dispersion values, or thicknesses Reconstructed specifications L. Ermenyi , Dr. Josef Petzvals Leben und Verdienste, Halle a. S., Verlag von Wilhelm Knapp, p. 25, 1903 Commercial camera: Voigtländer‐Petzval conical brass camera Plate D=92 mm ; f=149 mm Plate D=94 mm ; f=150 mm Measurements: 37 cm X 31 cm X 15 cm NATIONAL BANK OF SLOVAKIA An early Petzval objective from 1846 #2761 (1846) Aperture stop was the rim of the first doublet http://www.antiquecameras.net/petzvallens.html First‐order concept layout F1=16 Zoll F1=8 Zoll F2=24 Zoll F2=12 Zoll F=11 Zoll F=5 ½ Zoll D=5.1 Zoll D=2.55 Zoll Aperture 3 zoll Aperture 1 ½ zoll F/3.67 F/3.67 Petzval’s report of 1857 Thin lens solution Given by J. Eder N Crown = 1.517 N Flint = 1.575 The secret of the thin achromatic doublet is that the ratio of the optical powers of the individual lenses must be equal to the negative of the ratio of the glasses v‐numbers. Petzval statement of 1857 “Greater illumination, one of the desired improvements, can only be obtained in two ways – by enlarging the aperture and by diminishing the focal length, both which, however, will result from employing two converging lenses, instead of one. These lenses must of course be achromats; and by theory, in order that a good image may be produced, they must be separated from each other by a distance no less than one third of the focal length of the lens near the object.” Petzval 1857. Supports: Use of a thin lens model Use of third‐order theory Third‐order thin lens solution • Two achromatic doublets individually corrected for spherical aberration • Front doublet contributing positive coma and positive astigmatism • Rear doublet contributing negative coma and negative astigmatism • Field was artificially flattened W222 / W220P = ‐0.79. As a thin lens F1=8 Zoll F2=12 Zoll D=F1 / 3 Zoll W222 / W220P = ‐0.79. AB k uWWB 2 222 222 A 13 kuB W131 Thick lens solution W131 = 0 W131 = 0 Separation is D = 2 Zoll (Rather than D = 2.67 Zoll) W222 / W220P = -0.44 Lens Adjustment Voigtländer wrote: “Prof. Petzval and I finding that, by this ring (i.e. a spacer) we could compensate for some errors, which must have taken place in the calculation.” Petzval did not use real ray tracing. Some arguments are: • His two criticisms of the calculating opticians in his 1843 report and his repetitive highlighting of aberration theory. • His remark in his 1843 report that he had calculated 15 lens combinations with images of the fifth‐order (meaning a third‐order correction or several third‐order aberrations corrected). • That the distance between doublets in the portrait objective is at odds with Petzval’s remark of at least 1/3 the focal length of the first doublet. Further, this statement reflects a third‐order calculation. • That as late as 1857 Petzval expressly remarked that his new lens was corrected to an image of the fifth‐order. • The correction of chromatic change of focus using a thin lens model. K. &. K Bombardier – Corps This first result was the motive, because of the hopes to which it gave rise, that I was given authority by the highest order of his majesty, Archduke Karl Ludwig of Austria his k. & k. Highness General Artillery Director Arch Duke Ludwig to 30 July 1833 – 19 May 1896 have the members of the K. &. K Bombardier – Corps namely the two https://en.wikipedia.org/wiki/Archduke_Karl_Ludwig_of_Austria Oberfeuerwerkers Löschner and Hain at my disposal. This Bombardier corps was well known to have mathematical knowledge… A common misunderstanding Petzval in his 1843 report explains that the first practical result of his dioptric theory was the portrait objective of 1840. He writes that this first result was the motive for which Arch Duke Ludwig provided to him the help of the K&K Bombardier Corps. Later in 1903 L. Ermenyi wrote that before the end of 1840 the portrait lens became vividly discussed in Vienna and that the imperial court showed such interest that Arch Duke Ludwig provided to Petzval help with the Bombardier Corps. Accordingly, and contrary to common belief, Petzval did not have calculation help from the K&K Bombardier Corps to design his famous portrait lens. The Bombardier Corps helped Petzval to calculate the 15 tables (lens prescriptions) for Telescopes, cameras obscuras, and microscopes he wrote about at the close of his report of 1843. Petzval’s drawings "I have conquered the light, I have it firmly in my hands, because there is too much darkness in the world." L. Ermenyi [Dr. Josef Petzvals Leben und Verdienste], Halle a. S., Verlag von Wilhelm Knapp, 1903. Petzval lens specs • F/# 3.6 • F=150 mm • D=42 mm • FOV=+/‐ 16.5 degrees • All glass lenses Conclusion • Petzval, Voigtländer and Martin left enough information to understand how Petzval designed his famous portrait lens. In fact, we showthatPetzvalfollowedwhatitistaughtinintroductorylens design courses. This is first‐order layout, correction of chromatic aberration using doublets, correction of spherical aberration and coma, and artificially flattening the field of view. On‐axis irradiance ds'' da dL ''24 cos' 0 s '2 ds ' dI''cos' L 4 0 s '2 aU4 ' LL''r 22 Ir'20 drLdnU 2 'sincos 0 'sin' 002 22 2 sn''00rs ' L ' INA' 0 2 Radiance theorem 0 n'2 L00' L 22 2 1 nn' sinU ' 2 4/#F Object and image .