The Petzval objective, or Petzval lens, is the first photographic

portrait A portrait is a painting, photograph, sculpture, or other artistic representation of a person, in which the face is always predominant. In arts, a portrait may be represented as half body and even full body. If the subject in full body better r ...

objective lens In optical engineering, an objective is an optical element that gathers light from an object being observed and focuses the light rays from it to produce a real image of the object. Objectives can be a single lens or mirror, or combinations of ...

(with a 160 mm

focal length The focal length of an Optics, optical system is a measure of how strongly the system converges or diverges light; it is the Multiplicative inverse, inverse of the system's optical power. A positive focal length indicates that a system Converge ...

) in the history of

photography Photography is the visual arts, art, application, and practice of creating images by recording light, either electronically by means of an image sensor, or chemically by means of a light-sensitive material such as photographic film. It is empl ...

. It was developed by the Slovak mathematics professor Joseph Petzval in 1840 in

Vienna Vienna ( ; ; ) is the capital city, capital, List of largest cities in Austria, most populous city, and one of Federal states of Austria, nine federal states of Austria. It is Austria's primate city, with just over two million inhabitants. ...

, with technical advice provided by . The

Voigtländer Voigtländer () was a significant long-established company within the optics and photographic industry, headquartered in Braunschweig, Germany, and today continues as a trademark for a range of photographic products. History Voigtländer was fo ...

company went on to build the first Petzval lens in 1840 on behalf of Petzval, whereupon it became known throughout Europe. Later, the optical instruments maker Carl Dietzler in Vienna also produced the Petzval lens.

History

The Voigtländer-Petzval objective lens was revolutionary and attracted the attention of the scientific world because it was the first mathematically calculated precision objective in the history of

. Petzval's lens established two new features: firstly, it was faster compared to previous lenses, with a maximum aperture of 1:3.6. In comparison to Daguerre's

daguerreotype Daguerreotype was the first publicly available photography, photographic process, widely used during the 1840s and 1850s. "Daguerreotype" also refers to an image created through this process. Invented by Louis Daguerre and introduced worldwid ...

camera lens of 1839, Petzval's design had 22 times the light-gathering capacity, which for the first time enabled

portraits A portrait is a painting, photograph, sculpture, or other artistic representation of a person, in which the face is always predominant. In arts, a portrait may be represented as half body and even full body. If the subject in full body better re ...

under favourable conditions with exposure times of less than a minute. Additionally, Petzval calculated for the first time the composition of the lenses based on optical laws, whereas

optics Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of optical instruments, instruments that use or Photodetector, detect it. Optics usually describes t ...

before had previously been ground and polished according to experience. For the calculations, 8 artillery gunners and 3 corporals were made available to Petzval by Archduke Louis of Austria (commander of the

artillery Artillery consists of ranged weapons that launch Ammunition, munitions far beyond the range and power of infantry firearms. Early artillery development focused on the ability to breach defensive walls and fortifications during sieges, and l ...

), since the artillery was one of the few professions in which mathematical calculations were made. By 1845, Petzval's collaboration with Voigtländer, who held the license to produce the lenses, had become "mired in disputes". Voigtländer moved production outside of Austria and therefore beyond Petzval's patent limitations. The Petzval objective was produced by Voigtländer and sold worldwide; by 1862, Voigtländer had produced 60,000 pieces. One disadvantage of Petzval's design was a sharp drop in sharpness at the edges, which was corrected in the Aplanat lens developed by .

Optical design

The lens consisted of two doublet lenses with an

aperture stop In optics, the aperture of an optical system (including a system consisting of a single lens) is the hole or opening that primarily limits light propagated through the system. More specifically, the entrance pupil as the front side image of ...

in between. The front lens is well corrected for

spherical aberrations A sphere (from Greek , ) is a surface analogous to the circle, a curve. In solid geometry, a sphere is the set of points that are all at the same distance from a given point in three-dimensional space.. That given point is the ''center'' o ...

but introduces

coma A coma is a deep state of prolonged unconsciousness in which a person cannot be awakened, fails to Nociception, respond normally to Pain, painful stimuli, light, or sound, lacks a normal Circadian rhythm, sleep-wake cycle and does not initiate ...

. The second doublet corrects for this and the position of the stop corrects most of the

astigmatism Astigmatism is a type of refractive error due to rotational asymmetry in the eye's refractive power. The lens and cornea of an eye without astigmatism are nearly spherical, with only a single radius of curvature, and any refractive errors ...

. However, this results in additional

field curvature Petzval field curvature, named for Joseph Petzval, describes the optical aberration in which a flat object normal to the optical axis (or a non-flat object past the hyperfocal distance) cannot be brought properly into focus on a flat image plane ...

and

vignetting In photography and optics, vignetting ( ) is a reduction of an image's brightness or saturation toward the periphery compared to the image center. The word '' vignette'', from the same root as ''vine'', originally referred to a decorative b ...

. The total

field of view The field of view (FOV) is the angle, angular extent of the observable world that is visual perception, seen at any given moment. In the case of optical instruments or sensors, it is a solid angle through which a detector is sensitive to elec ...

is therefore restricted to about 30 degrees. An

f-number An f-number is a measure of the light-gathering ability of an optical system such as a camera lens. It is calculated by dividing the system's focal length by the diameter of the entrance pupil ("clear aperture").Smith, Warren ''Modern Optical ...

of 3.6 was achievable, which was considerably faster than other lenses of the time.

Lens revival

Between 1962 and 1972, the United States used a petzval lens in the KH-4 through KH- 4B cameras. Produced by Itek, These cameras were a part of the CORONA satellite program. This program was a secret photoreconnaissance satellite program meant to image the Earth's surface and targeted nations such as the USSR. At the end of the program, the camera resolution was about two meters. In 2013,

Lomography Lomography, or simply lomo, is a photographic style which involves taking spontaneous photographs with minimal attention to technical details. Lomographic images often exploit the unpredictable, non-standard optical traits of toy cameras (such as ...

successfully launched a

crowdfunding Crowdfunding is the practice of funding a project or venture by raising money from a large number of people, typically via the internet. Crowdfunding is a form of crowdsourcing and Alternative Finance, alternative finance, to fund projects "withou ...

campaign at kickstarter.com to produce a new Petzval lens in Russia for film and digital cameras. Lensbaby offers Petzval lenses for modern cameras under the Burnside and Twist names. In 2019 TLS rehoused the Lomography lens for use on professional cinema cameras using the PL mount. The 58mm and 85mm versions were used in the 2023 feature film Poor Things.

Petzval telescopes

A petzval telescope is a type of refractor telescope that follows the design of the petzval lens system. These petzval telescopes are widely used in astrophotography due to their well-corrected optics. Unlike most refractors and reflectors, petzval telescopes have a uniform, distortion-free image across the entire field of view. In standard refractors, the curvature of the front objective lens can cause stretched or elongated stars. This requires astronomers to use a corrective field-flattener or field-flattener reducers to correct the distortion. However, with a petzval lens design, the second lens group is used to correct for this curvature, eliminating the need for a field-flattener. Many of the petzval designed telescopes are quadruplets designs, containing four glass elements within the telescope. At least one of these glass elements, typically in the front optic, is extra-low dispersion glass (ED). ED glass help reduce chromatic aberrations which helps with color accuracy and image quality. Petzval telescopes are mainly marketed towards astrophotographers as the flat-field and well-corrected optics make it ideal for imaging. Some petzval telescopes include a visual back allowing for visual use, however some designs do not include one.

Image gallery

File:Petzval03.png, Cross section view of Petzval objectives: Portrait objective (German ''Porträtobjektiv'') and

ocular lens An eyepiece, or ocular lens, is a type of lens that is attached to a variety of optical devices such as Optical telescope, telescopes and microscopes. It is named because it is usually the lens that is closest to the eye when someone looks thro ...

(German ''Orthoskop''). File:Katherine Maher.jpg, An example of a portrait photo (of

Katherine Maher Katherine Roberts Maher ( ; born April 18, 1983) is an American non-profit executive. She has been the chief executive officer (CEO) and president of the National Public Radio since March 2024. Prior to NPR, she was the CEO of Web Summit and ...

) taken with a

-produced Petzval lens. Note the unique 'swirly'

bokeh In photography, bokeh ( or ; ) is the aesthetic quality of the blur produced in out-of-focus parts of an image, whether foreground or background or both. It is created by using a wide aperture lens. Some photographers incorrectly restr ...

. File:Petzval1.png, Petzval type movie projection lens.

References

{{reflist Photographic lenses Hungarian inventions Austrian inventions