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Application of Lenses : Camera

We know in common the usage of lenses in magnifiers, cameras, microscopes and telescopes. These four optical equipments discussed in most physics textbooks for yunior or high school students and have lenses as the vital parts.

Actually there are more and more equiptments using lens or lenses for component for instance eye glasses, contact lens, projector, printer, scanner, periscope. In this short article we will discussed a camera as our topic.

The basic elements of a camera

A camera should have these parts as its components, nowadays many components are added to gain the high results of the image produced.

Remember the procces of formation image for a converging lens. Put an object, locate outside the focal point and greater in distance than 2f of your lens. There will be a real image, inverted, and smaller in size than the object. Put a sheet of paper in the location of the image, done, you already have a camera. The camera obscura or pinhole of ancient cameras use this principle also.

The problem is how to catch the image of course a sheet of paper is not proper enough for this purpose, a recording medium is needed and you shouldn't redraw the image by your pen instead. Old camera uses photograpich films or a light sensitive surface for this purpose. In digital camera it is replaced by an electronic detector called a CCD (charge coupled device).

1) converging lens
2) recording medium
3) shutter
4) aperture control diaphragm

Converging lens needed to form a real image of the object to be placed in recording medium. A shutter and aperture will control the amount of light striking recording medium.

For addition of course there is camera body to hold and placing control devices. The lens of camera should be moved in or out for different objects distance and the ability of a camera to adjust the light striking is one important factor to get high quality of image results.


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