Petzval’s portrait

Lens Design OPTI 517

Prof. Jose Sasian Chronology

• obscura; Leonardo da Vinci (1452- 1519) provided the first known technical description • The idea of capturing an image • Lois Jacques Mande Daguerre (1787-1851) succeeded in finding a photographic process. This was announced in 1939

Prof. Jose Sasian Announcement of the invention of the by Arago at the meeting of the French Academy of Sciences and Arts

August 19th 1939

Louis-Jacques- Mandé Daguerre

Dominique François Arago

Prof. Andreas Ettingshausen, 1796–1878

Prof. Jose Sasian 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-. 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 placed before at a distance of 3 zoll from the lenses.” J. Petzval

Prof. Jose Sasian Prof. Ettingshausen asked to explore the shape of the lenses

Joseph Petzval University, 19th century Prof. Andreas Ettingshausen 1807-1891

“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 the objectives used in Daguerre’s by my dear friend and colleague Professor von Ettingshausen. I was asked to explore the reason for this shape.” J. Petzval

Prof. Jose Sasian Petzval Portrait Lens “Greater illumination, one of the desired improvements, can only be obtained in two ways – by enlarging the and by diminishing the , 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

Prof. Jose Sasian Joseph Eder’s remark

“The commercial success of the Petzval portrait lens was immediate and extraordinary, and that it spread with unexpected rapidity.”

Prof. Jose Sasian imaging

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.

Prof. Jose Sasian 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 1839 • Petzval had his designed done by May 1840, likely by March.

Prof. Jose Sasian Prof. Ettingshausen suggests to P. W. Voigtländer to talk to Petzval

P. W. F. Voigtländer, lens manufacturer in Vienna

Prof. Andreas Ettingshausen

Prof. Jose Sasian P. W. Voigtländer meets Petzval and provides glass indices of refraction and dispersion values

P. W. F. Voigtländer

Joseph Petzval

Prof. Jose Sasian Petzval produces by May of 1840 two objective designs (actually four)

For For “views” (landscapes) portraits

Prof. Jose Sasian First camera with the Petzval Portrait objective

• Voigtländer manufactured the objectives • The portrait objective working at F/3.67 allowed taking in seconds (~40) making portrait a practical reality. • Anton Martin took photographs to evaluate the lens

Anton Martin

Prof. Jose Sasian 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

Prof. Jose Sasian P. W. F. Voigtländer notarized copy

Akademiker Prof. Dr. Petzval, beleuchtet von Voigtländer, Drud und Berlag von Friedrich Biemeg und Gobn, NATIONAL BANK OF SLOVAKIA Braunschweig 1859.

Prof. Jose Sasian 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

Prof. Jose Sasian Reconstructed specifications

Prof. Jose Sasian 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

Prof. Jose Sasian An early Petzval objective from 1845

Aperture stop was the rim of the first doublet

Prof. Jose Sasian 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 F/3.67 zoll F/3.67

Petzval’s report of 1857

Prof. Jose Sasian 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 of the ratio of the glasses v-numbers.

Prof. Jose Sasian 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

Prof. Jose Sasian Third-order thin lens solution

• Two achromatic doublets individually corrected for • 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 Prof. Jose Sasian Thick lens solution

W131 = 0

W131 = 0 Separation is D = 2 Zoll (Rather than D = 2.67 Zoll)

W222 / W220P = -0.44

Prof. Jose Sasian 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.”

Prof. Jose Sasian 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 using a thin lens model.

Prof. Jose Sasian 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, his k. & k. Highness General Artillery Director Arch Duke Ludwig to have the members of the K. &. K Bombardier – Corps namely the two Oberfeuerwerkers Löschner and Hain at my disposal. This Bombardier corps was well known to have mathematical knowledge…

Prof. Jose Sasian 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, obscuras, and microscopes he wrote about at the close of his report of 1843.

Prof. Jose Sasian Petzval’s drawings

Prof. Jose Sasian "I have conquered the light, I have it firmly in my hands, because there is too much darkness in the world."

Prof. Jose Sasian Petzval lens specs

•F/# 3.6 • F=150 mm • D=42 mm • FOV=+/- 16.5 degrees • All glass lenses

Prof. Jose Sasian Time table

1812 W. Wollaston landscape lens; 30 deg @ f/15 1825 ~T. Young, G. Airy, J. Herschel, H. Coddington 1828 Hamilton's theory of systems of rays 1839 Photography was made a practical reality 1839 Chevalier lens 1840 Petzval (Hungarian) portrait lens; 15 deg @ f/3.6 1841 Gauss’s cardinal points, focal and principal 1856 Seidel theory

Prof. Jose Sasian The state of the art

• Telescope doublets: and spherical aberration • Periscopic lenses in the camera obscura ~1812 • Airy’s study of the periscopic lens exhibiting the trade of between astigmatism and field curvature. • H. Coddington treatise in ~1829 • Microscopes • J.J. Lister microscope which was aplanatic 1830 • Precise measurement of index of refraction by Fraunhofer ~1812

Prof. Jose Sasian State of the art in the field of lens design

Prof. Jose Sasian Petzval lens stop at first lens

Prof. Jose Sasian Relative illumination

Prof. Jose Sasian Light

Light is limited by the physical of the lenses. This reduces aberration and improves image quality at the expense of light and illumination uniformity.

Prof. Jose Sasian Light vignetting

Prof. Jose Sasian Prof. Jose Sasian Prof. Jose Sasian F-stops

F/1.4 F/2 F/2.8 F/4 F/5.6 F/8 F/16 F/22 1 sec. 2 sec. 4 sec. 8 sec. 16 sec. 32 sec. 64 sec. 128 sec.

One F-stop step doubles the time

Prof. Jose Sasian How much vignetting?

It does depend on application.

One F-stop might be acceptable in photography

0.0%, 50% 75% 87.5%

Prof. Jose Sasian Field flattener lens

Prof. Jose Sasian Other lenses based on the Petzval lens

Prof. Jose Sasian Lens forms

Prof. Jose Sasian Using a Petzval lens

• If I can use a Petzval type lens I will do it! • It is a relaxed lens in that the optical power of the parts contributes to the total power. • The individual doublet lens optical power efficiently contributes to the total power.

Prof. Jose Sasian