'''texto a negrito'''

O termo "'''objetivo'''" diz respeito a um fim que se quer atingir. É o '''cume''' de uma busca, é quando você tem em mente '''onde''' e '''quando''' quer chegar. Objetivo nada mais é que a luz fim do túnel, o '''lugar''' ou '''objeto''' que você tanto deseja.
Podemos apresentar como exemplo aquele carro que tanto cobiça, um  emprego que você batalha para alcançar, um futuro que você Planeja.
“A pessoa que não tem '''Objetivo''' na vida não tem porque de viver” (Bento Junior)
“O sentido da Vida é o '''Objetivo''' a ser alcançado” (Bento Junior)

A definição clara de objectivos é de extrema importância em várias áreas de actuação humana, a nível administrativo e de gestão, orientando a acção dos indivíduos. Em educação, por exemplo, a definição de actividades curriculares deve ser feita tendo em vista os objectivos definidos no programa curricular dos alunos.

==Administração==
Dentro da visão estruturalista administrativa (vide Administração), o objetivo é um dos componentes que diferenciam um sistema artificial de um sistema natural. Nas modernas teorias, o objetivo pode receber outros nomes, que podem ser visto como sinônimos ou evidenciarem uma conotação crescente mais abstrata, tais como metas, visão etc (vide objetivos organizacionais).

Outros componentes de um sistema artificial administrativo:

thumb|right|250px|A photographic lens: the [[Canon_EF_50mm_lens#EF_50mm_f.2F1.4_USM|Canon's EF 50mm F1.4 USM, an example of a prime lens (single focal length lens) and normal lens]]
A '''photographic lens''' (also known as '''objective lens''' or '''photographic objective''') is an optical lens or assembly of lenses used in conjunction with a camera body and mechanism to make images of objects either on photographic film or on other media capable of storing an image chemically or electronically.
While in principle a simple convex lens will suffice, in practice a compound lens made up of a number of optical lens elements is required to correct (as much as possible) the many optical aberrations that arise.  Some aberrations will be present in any lens system.  It is the job of the lens designer to balance these out and produce a design that is suitable for photographic use and possibly mass production. 

There is no major difference in principle between a lens used for a camera, a telescope, a microscope, or other apparatus, but the detailed design and construction are different.  

A lens may be permanently fixed to a camera, or it may be interchangeable with lenses of different focal lengths, apertures, and other properties.

== Construction ==
thumb|250px|The [[zoom lens assembly of the Canon Elph]]

A practical camera lens will most often incorporate an aperture adjustment mechanism, usually an iris diaphragm, to regulate the amount of light that may pass. In early camera models a rotating plate or slider with different sized holes was used. These shutter, to regulate the time during which light may pass, may be incorporated within the lens assembly (for better quality imagery), or may be within the camera, or even, rarely, in front of the lens.  Some cameras with leaf shutters in the lens omit the aperture, using the shutter to perform this function.

The lens may usually be focused by adjusting the distance from the lens assembly to the image-forming surface, or by moving elements within the lens assembly.  Some lenses include a cam system which may vary the distance between the groups to provide better performance when the lens is focused at different distances.  This system is usually referred to differently by different manufacturers for marketing purposes.  Nikon calls this technology CRC (close range correction) while Hasselblad uses the term FLE (floating lens element)[http://photonotes.org/cgi-bin/entry.pl?id=Floatingelement].

The lens elements are made of transparent materials. acrylic (the material of Plexiglass) can also be used. Occasionally, even meteoritic glass have been used.<ref>{{cite web | url=http://www.luciolepri.it/lc2/marcocavina/articoli_fotografici/articolo_obiettivi_uv.pdf | title=Fuori banda: gli obiettivi per fotografia multispettrale della Asahi Optical Co | language=Italian | format=PDF | first=Marco | last=Cavina | date=August 25 2006 | accessdate=2007-11-05 | quote=Rank Taylor Hobson IRTAL II 100mm f/1.0, an example of specific target for recovery in the IR spectral range of 2000 nm with lenses made of
Germanium, transparent these wavelengths extremely high but completely opaque to visible light. ... In the'50s A swarm of iron meteorites impact to states in the Northeast USA; It was pallasiti, or beautiful Aeroliti metal that hard crystalline nuclei, usually Peridot or olivine say that we want (a mixture Isomorphic with nesosilicato iron bivalent and nesosilicato magnesium which must be green, in fact, the iron In the first component, called fayalite, borrowed from the matrix ferrous), but the exceptional of these meteorites Was that the crystal nuclei were fully incorporated transparent and free of impurities as the best glass Optical; Mr.. Wollensak was aware of this curious anomaly, and I think immediately to exploit this "glass" Achieving: purchase a large quantity of these abnormal pallasiti, extracting and testing the crystalline material Transparent; Immediately he realized that it was amorphous quartz and devoid of negative characteristics of Earth's natural crystalline material (polarization, birifrangenza, etc.). ; Surveys spectrophotometry Evidenziarono that the quartz alien sent well frequencies of ultraviolet deep, beautiful beyond the threshold 320 nm granted by conventional optical glass, providing partial transparency to the fateful threshold of 200nm!}}</ref> Plastics allow the manufacture of strongly aspherical lens elements which are difficult or impossible to manufacture in glass, and which simplify or improve lens manufacture and performance. Plastics are not used for the outermost elements of all but the cheapest lenses as they scratch easily. Moulded plastic lenses have been used for the cheapest disposable cameras for many years, and have acquired a bad reputation: manufacturers of quality optics tend to use euphemisms such as "optical resin".  However many modern, high performance (and high priced) lenses from popular manufacturers include molded or hybrid aspherical elements, so it is not true that all lenses with plastic elements are of low photographic quality.  

The multi-coated in order to minimize lens flare and other unwanted effects. Some lenses have a UV coating to keep out the ultraviolet light that could expose photosensitive materials and result in inaccurate colors.  Most modern optical cements which are used for bonding two glass elements together block UV light quite efficiently, which negates the need to use UV filters with most lenses.  UV photographers will go to great lengths to find lenses that they can use effectively for their work, converting lenses with no cemented elements for possible UV work by polishing away the lens coatings, if present.

== Aperture and focal length ==
thumb|right|250px|Nikon's AF-S DX Zoom-Nikkor 18&ndash;70 f/3.5–4.5G IF-ED, an example of a lens with a zoom (focal length that can change), and a lens with a variable maximum aperture (the widest aperture changes as you zoom)
thumb|right|250px|The Canon 85mm f/1.8 is a compact lens popular with portrait photographers. Its large aperture can be used to minimize flash requirements or to produce a shallow depth of field.

The two main optical parameters of a photographic lens are the maximum aperture and the focal length. The focal length determines the angle of view, and the size of the image relative to that of the object, while the maximum aperture limits the brightness of the image and the fastest shutter speed usable. A popular third consideration is close focusing distance.

The maximum usable aperture of a lens is usually specified as the focal ratio or SLR cameras to focus with a brighter image with shallower depth of field, theoretically allowing better focus accuracy. 

Focal lengths are usually specified in millimetres (mm), but older lenses marked in centimetres (cm) and inches are still to be found. For a given film or sensor size, specified by the length of the diagonal, a lens may be classified as

*Normal lens: angle of view of the diagonal about 50° and a focal length approximately equal to the diagonal produces this angle. <!-- It's generally accepted that 50mm is a bit longer than "normal" for 35mm film; I've based this on 75mm with 6×4cm. Maybe the angle of width, rather than diagonal, is better? -->
* Macro lens: angle of view narrower than 25° and focal length longer than normal. These lenses are used for close-ups, e.g., for images of the same size as the object. They usually feature a flat field as well, which means that the subject plane is exactly parallel with the film plane.
*Wide-angle lens: angle of view wider than 60° and focal length shorter than normal.
*Telephoto lens or long-focus lens: angle of view narrower and focal length longer than normal. A distinction is sometimes made between a long-focus lens and a true telephoto lens: the telephoto lens uses a ''telephoto group'' to be physically shorter than its focal length.

The 35mm film format is so prevalent that a 90mm lens, for example, is sometimes assumed to be a moderate telephoto; but for the 7×5cm format it is normal, while on the large 5×4 inch format it is a wide-angle. In general, the smaller the film or sensor surface, the smaller the angle of view. This can be corrected with lenses with shorter focal lengths.

{| align="center"
|+ ''An example of how lens choice affects angle of view. The photos below were taken by a 35 mm camera at a constant distance from the subject.''
|-
| frame|28 mm lens 
| frame|50 mm lens
|-
| frame|70 mm lens 
| frame|210 mm lens
|}

A side effect of using lenses of different focal lengths is the different distances from which a subject can be framed, resulting in a different  perspective. Photographs can be taken of a person stretching out a hand with a wideangle, a normal lens, and a telephoto, which contain exactly the same image size by changing the distance from the subject. But the perspective will be different. With the wideangle, the hands will be exaggeratedly large relative to the head. As the focal length increases, the emphasis on the outstretched hand decreases. However, if pictures are taken from the same distance, and enlarged and cropped to contain the same view, the pictures will have identical perspective. A moderate long-focus (telephoto) lens is often recommended for portraiture because the perspective corresponding to the longer shooting distance is considered to look more flattering.

== Number of elements ==