Objectively (optics)

Nikon 18-70 mm-objectively
Nikon 50 mm-objectively with maximally opened screen
camera with objective
Vivitar-Vergrößerungsobjektiv VHE 50 mm/1:3,5
Vivitar Vergrösserungsobjektiv VHE 50 mm/1: 3,5

an objective is a collecting optical system, which produces a real optical illustration of an object. Both lenses and reflecting surfacescan components of an objective be. Exactly like the object the produced picture is three-dimensional. Objects, which are very far distant, thus apparently in the infinite one lie, (e.g. Stars and other objects in the sky) are illustrated in one level, the image plane.

The size of the picture depends on the focal length of the lens. The more largely this, the more largely is also the picture. In order to be able to use the camera for lenses of different focal length, it provide was with an excerpt (bellow), thatit permitted to extend it and/or. to shorten; the bellow principle is used also today still in that large picture - and macro photography.

Table of contents

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Systematics

one differentiate objectives primarily due to its focal length; distinctive between

The categories specified above apply to fixed focal length objectives; very popular nowadays meanwhile zooms are, those the change that in the amateur photographyFocal length to permit and depending upon focal length ranges also several of the categories mentioned to take off know. Zooms are categorized also after their relative focal length range and are the heavy and more complex, them are the brighter and the a larger relation between longer and more brieflyFocal length it cover.

Further important distinguisher is differently expressed the initial opening, or: as bright an objective is.

In addition objectives can be differentiated according to different constructional characteristics, e.g.

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basic constructions

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Use

a projector uses an objective, in order to project a standing or moved picture increased on a wall.

In a microscope or a telescope one regards the picture produced by the objective very smaller or far objects throughan eyepiece, a further lens system. With the microscope thereby the image plane lies more near with the objective, and the objective has a short focal length compared to the eyepiece. With the telescope the image plane is more near because of the eyepiece, and the objective has the larger Focal length.

In the photography or video technology the objective is part of a camera and/or a video camera. It produces a real picture in the image plane, where the photo-sensitive film or an electronic sensor is. One differentiates on the basis the focal length between wide angle objectives, normal objectives and telephotos. If the focal length of the objective can be changed, one speaks of a zoom, otherwise of a fixed focal length. Special objectives are the fish eye (Fisheye) and TS-objectives.

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history and development

tooprogress of the photography in the second half 19. Century the numerous perfections of the objectives contributed. In former times one used simple achromatic lenses, which pictures sharp for achievement had to become strongly “dipped the headlights”. Consequently they gave very faint pictures,the one long exposition time made necessary.

A large progress was the invention of the haven guessing objective of Josef Petzval, a fast lens, which consists of two double lens systems, importantly brighter pictures supplied than previous and thus the admission of haven advice in shorterExposition time made possible. For the admission of landscapes, architectures etc. less luminous intensity, but a large aspect is necessary.

The usual landscape objects cover only one angle from 30° to 45°, which is usually too small. One used for it in former times excluding simple lenses, laterbut the Tripletobjektive, approximately starting from the 1860er years then the aplanatic lenses introduced by stone welfare. The Tripletobjektive is an objective, which possesses altogether three lenses. To this system also the Euriskope , the rapidly Rectilinear belongs among other things

These adda visual field of approx. 60° a sufficient luminous intensity, in order to permit in cheerful summer weather snapshots. If a still larger visual field than 60° is necessary, then one takes wide angle lenses, like Buschs Pantoskop, Dallmeyers Wide fishes lens, stone welfare wide angle aplanatic lens, Voigtländers Weitwinkeleuriskop, which possess a visual field from 75 to 100°.

In the year 1860 Thomas's Suez clay/tone designed a symmetrical Tripletlinse; the objective consisted thereby of two convex lenses whose front was smaller around for instance a third than thoseHinterlinse, as well as a further Einzellinse than concave meniscus.

Stone welfare periscope objective of 1865 is a distortion-poor objective with large picture angle, the first wide angle objective in the today's understanding.

Ludwig Seidel examined the aberrations of the lenses in Munich and published 1866 a formula system,that the objective construction facilitated.

Hugo Adolf stone welfare designed 1881 the first universal objective.

Ernst Abbe and Otto bulkhead began at 1880 with the development of new glass sorts. They created 1882 together with Carl Zeiss a Glasschmelzerei in Jena. With the help of thatnew glasses succeeded it after 1886 to the coworker Paul Rudolph to design a Doppelobjektiv with which the error of the astigmatism was for the first time corrected: the planar - objective.

The astigmatism can be corrected also by use of aspheric lenses, however inthe production are many more complicated as spherical lenses.

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objective manufacturer

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literature

  • H. E. Fincke: The objective of your camera (2. neubearb. Aufl.). Resounds: Photo cinema publishing house 1963
  • Johannes Flügge: The photographic objective (the scientific and applied photography, hrsg. v. Briefly Michel, volume 1). Vienna: Springer publishing house 1955
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Web on the left of

 

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