Tilt Shift in Landscape Photography
Tilt shift is a photographic technique achieved with tilt shift lenses. It's a useful tool that can help photographers overcome perspective problems caused by the laws of optics. Tilt shift can be especially useful in landscape photography.
Correcting Perspective Problems
According to the laws of physics, the subject plane needs to be parallel to the image plane in order for parallel lines in the subject to remain parallel in the photograph. If that does not happen, then a false perspective will be created that the lines are going to converge as the distance from the image plane increases. The shift movement in a tilt shift lens can correct this problem by altering the angle of the lens without moving the camera position.
So, why is this useful for landscape photography? Well, if you're going out to shoot of a wide area, then the odds are pretty good that there will be objects in your frame with straight lines like trees. Under normal circumstances, the chances are pretty good that these trees might get distorted by the camera's ordinary lens. But, if you're employing a tilt shift lens, you can correct the problem by adjusting the shift.
Altering the Depth of Field
The tilt feature in a tilt shift lens allows the photographer to alter the angle of their depth of field in a frame. In an ordinary lens, the sharp focus area runs in an imaginary straight line that is parallel to the lens. By adjusting the tilt, you can alter the angle of that line so that it intersects with the imaginary line the lens rests on. This can result in having objects that are in sharp focus at both ten and twenty feet away from the lens as long as they rest on the same focus plane.