Elliptical Perspective

If you look at glass or jar from directly above, the opening will make a circle. If you were to look at the glass from the side, the opening appears to squish down in size, becoming an ellipse. Notice that the opening, elliptical shape, has curved outside edges, they are not the shape of a football which come to a point on the outside edges. If the opening of the glass were to be exactly level with eyes, the ellipse would narrow to look like a straight line. As you raise or lower the glass, above or below your eye level, the shape of the ellipse will get fatter the further above or below your eye level it travels.

 

Study the transparent cylinder below - it is divided into 4 sections that are parallel to one another. Notice how the elliptical shapes that define each section become rounder as they get father away from the viewer's eye level.

Notice that the ellipse will change horizontally as well as vertically