Vanishing Point

Vanishing Point, originally uploaded by Scott O. Smith.

van-ish-ing point
noun
the point at which receding parallel lines viewed in perspective appear to converge.

Vertical lines give a strong sense of depth and strength. They can provide structure and a clear definition by pointing the eye directly to the intended point. The image of the stream (bottom right) leads the eye straight to the point where the water disappears to the left.

While the most common/prefered curved line is the "S" curve, parallel lines can be very effective. The image in the hallway(bottom left) leads the eye straight to the door and leaves the viewer wondering what's on the other side.

Canon XTi, Canon EF-24-105mm f/4.0L lens, 1/60 second, f/4.0, ISO 100
Canon XTi, Canon EF-24-105mm f/4.0L lens, 1/40 second, f/8.0, ISO 100
Canon XTi, Canon EF-24-105mm f/4.0L lens, 1/10 second, f/4.0, ISO 100
Canon XTi, Canon EF-24-105mm f/4.0L lens, 1/200 second, f/8.0, ISO 200