Perspective distortion causes parallel lines appear to converge at a
long distance. We all are aware of this illusion. Wider the lens, more
acute is the distortion. While taking photograph of a tall building or
structure from a short distance with a wide-angle lens, the building appears
to be tilted. One way to correct this effect optically is to use a Tilt
and Shift lens. These lenses can be shifted and tilted with respect to
the focal plane to compensate this distortion. The problem is, they are
quite costly J However, we can achieve similar correction digitally by
using a simple technique in PhotoShop. Let me illustrate this on a photograph
of a window, taken obliquely with a wide-angle lens. The distortion is
very acute. After applying the technique the result is amazing!
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