In photography, perspective distortion pertains to transformation of a part scene or composition to be shot with respect surrounding area significantly due to the relative scale of nearby and distant features of the composition.
IN A sense, the perspective distortion is determined by how the relative distances at which the images in a composition have been captured. The extension distortion is also called the wide-angle distortion. In fact, the wider lenses tend to magnify distance between objects while allowing greater depth of field.
In the extension-distortion, the images are shot from close with a wide-angle lens and they appear abnormally large relative to more distant objects. Commonly, this type of distortion can be annoying, but when done for artistic purposes.
For artistic purposes, the extension distortion often enlarges the close by element of composition larger and spatially removed from the other elements. With a title in the camera along with extension distortion one can make vertical things appear to be falling backwards. Similarly, the changing the angle of view can indirectly distort perspective, changing the apparent relative size of the subject and background.
One must also experiment with this type of photography occasionally to make spaces around the subject appear vaster by increasing the distance between subject and background. The inset picture is an example extension-perspective distortion in which I have pointed the fingers of left and with camera in my right hand the picture of distant wall clock was taken.