Wide angle lens

Description of a wide angle lens from wikipedia.

http://en.wikipedia.org/wiki/Wide-angle_lens
From a design perspective, a wide angle lens is one that projects a substantially larger image circle than would be typical for a standard design lens of the same focal length; this enables either large tilt & shift movements with a view camera, or lenses with wide fields of view.

More informally, in photography and cinematography, a wide-angle lens refers to a lens whose focal length is substantially shorter than the focal length of a normal lens for the image size produced by the camera, whether this is dictated by the dimensions of the image frame at the film plane for film cameras (film format)[1] or dimensions of the photosensor for digital cameras.

By convention, in still photography, the normal lens for a particular format has a focal length approximately equal to the length of the diagonal of the image frame or digital photosensor. In cinematography, a somewhat longer lens is considered "normal".[2]

There is an easy formula for calculating the angle of view for any lens that produces a rectilinear image. In addition to giving a wider angle of view, the image produced by a wide-angle lens is more susceptible to perspective distortion than that produced by a normal lens, because they tend to be used much closer to the subject.


Heres some examples from flickr

http://www.flickr.com/photos/petecarr/476672999/in/photostream/