Showing posts with label focal length. Show all posts
Showing posts with label focal length. Show all posts

Wednesday, September 2, 2009

Lenses

What is the basic function of lens and its characteristic?

In digital photography the lens is the most important part of a camera that takes the light that enters the camera and focus it on single point to form a sharp image/s. Its basic function is to admits a large amount of light permitting proper exposure in a small fraction of a second.

Lens Characteristics
Lens speed - refer to the amount of light that a given lens can transmit in a given time. The aperture part of the lens that controls the amount of light that reaches the film or CCD in digital camera.

Focal length- the distance from the center of the lens to the sharp image produce on the film plane or CCD when focused on infinity.

In digital photography Lens are classified as:
1. Wide angle lens- lenses with a focal length of 35 mm and below.
2.Normal lens- lens not particularly wide angle and not telescopic. For SLR camera lens of 50mm
is considered to be normal lens.
3. Telephoto Lens- lenses with a focal length longer than the normal lens (above 50mm focal length).
4. Angle of Coverage- Sometimes referred to as Lens Field of View- depends upon its focal Length - the longer the focal length the smaller the angle view.


 
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