Prof. Jose Sasian

Petzval’s portrait lens

Lens Design OPTI 517

Prof. Jose Sasian

Chronology

• Camera 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 Daguerreotype by Arago at the meeting of the

French Academy of Sciences and Arts

Louis-Jacques-Mandé

Daguerre

Dominique François Arago

Prof. Andreas Ettingshausen, 1796–1878

August 19th 1939

Prof. Jose Sasian

Daguerre’s camera and the achromatic landscape lens

“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

½ hour to take a picture: F/16

Prof. Jose Sasian

Prof. Ettingshausen asked Joseph Petzval to explore the

shape of the lenses

Vienna University, 19th centuryJoseph Petzval1807-1891

“It was in the year 1839, when the wonderful invention byDaguerre was made public, and incited the general interestto such a high degree. At that time I was first made aware ofthe strange shape of the objectives used in Daguerre’scamera obscura by my dear friend and colleague Professorvon Ettingshausen. I was asked to explore the reason for thisshape.” J. Petzval

Prof. Andreas Ettingshausen

Prof. Jose Sasian

Petzval Portrait Lens

F/3.6 40 seconds to take a picture

“Greater illumination, one of the desired improvements, can only beobtained in two ways – by enlarging the aperture and by diminishingthe focal length, both which, however, will result from employing twoconverging lenses, instead of one. These lenses must of course beachromats; and by theory, in order that a good image may beproduced, they must be separated from each other by a distance noless than one third of the focal length of the lens near the object.”Petzval 1857.

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

Petzval lens 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 providesglass 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 “views” (landscapes) For 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 photographs in seconds (~40) making portrait photography 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 SLOVAKIA

Prof. Jose Sasian

P. W. F. Voigtländer notarized copy

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

Prof. Jose Sasian

The two sets of prescriptions

Given in linien, zoll, and zoll and linien old German units

In ink and in pencilNo 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 mmPlate 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

Petzval’s report of 1857

F1=8 ZollF2=12 ZollF=5 ½ ZollD=2.55 ZollAperture 1 ½ zollF/3.67

F1=16 ZollF2=24 ZollF=11 ZollD=5.1 ZollAperture 3 zollF/3.67

Prof. Jose Sasian

Thin lens solution

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.

Given by J. EderN Crown = 1.517N Flint = 1.575

Prof. Jose Sasian

Petzval statement of 1857“Greater illumination, one of the desired improvements, can only beobtained in two ways – by enlarging the aperture and by diminishingthe focal length, both which, however, will result from employing twoconverging lenses, instead of one. These lenses must of course beachromats; and by theory, in order that a good image may beproduced, they must be separated from each other by a distance noless than one third of the focal length of the lens near the object.”Petzval 1857.

Supports:

Use of a thin lens modelUse of third-order theory

Prof. Jose Sasian

Third-order thin lens solution

W222 / W220P = -0.79.As a thin lens

• 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

F1=8 ZollF2=12 ZollD=F1 / 3 ZollW222 / W220P= -0.79.

222 222

131

21 3

A BB

AB

u W Wkk u W

Prof. Jose Sasian

Thick lens solutionW131 = 0

W131 = 0Separation 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. aspacer) we could compensate for some errors, which must have takenplace 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 focus 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 misunderstandingPetzval in his 1843 report explains that the first practical result of his dioptric theory was the portraitobjective of 1840. He writes that this first result was the motive for which Arch Duke Ludwigprovided 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.

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/151825 ~T. Young, G. Airy, J. Herschel, H. Coddington1828 Hamilton's theory of systems of rays1839 Photography was made a practical reality1839 Chevalier lens 1840 Petzval (Hungarian) portrait lens; 15 deg @ f/3.61841 Gauss’s cardinal points, focal and principal1856 Seidel theory

Prof. Jose Sasian

The state of the art• Telescope doublets: Chromatic aberration 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 optics ~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 vignetting

Light is limited by the physical apertures 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/221 sec. 2 sec. 4 sec. 8 sec. 16 sec. 32 sec. 64 sec. 128 sec.

One F-stop step doubles the exposure time

Prof. Jose Sasian

How much vignetting?

0.0%, 50% 75% 87.5%

It does dependon application.

One F-stop might beacceptable in photography

Prof. Jose Sasian

Field flattener lens

Prof. Jose Sasian

Other lenses based on thePetzval 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.