How does a telephoto lens work?

Watch this video http://www.ehow.com/video_5112943_telephoto-lens-work.html and check out the website below


http://en.wikipedia.org/wiki/Telephoto_lens

In photography and cinematography, a telephoto lens is a specific construction of a long focal length photographic lens in which the physical length of the lens is shorter than the focal length. In these lenses the optical centre lies outside of its physical construction, such that the entire lens assembly is between the optical centre and the focal plane. A regular lens of a focal length that is longer than what is considered a normal lens is not necessarily a telephoto lens. A telephoto lens has to incorporate a special lens group known as a telephoto group; nevertheless, non-telephoto lenses of long focal length are often informally referred to as telephoto lenses. The angle of view created by a telephoto lens is the same as that created by an ordinary lens of the same specified focal length.

Hey vardhan83 you can't just paste text in without giving the website credit which is the wikipedia link I gave in my post.

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