Wide cone shapes produce shallow depth of fields. This is because the in focus part is at the point of convergence. As the point becomes a circle, and the circle becomes bigger, there is less focus. So for a wide cone, the point becomes a big circle quickly, so the depth of field is shallow.

Wide cone shapes produce shallow depth of fields. This is because the in focus part is at the point of convergence. As the point becomes a circle, and the circle becomes bigger, there is less focus. So for a wide cone, the point becomes a big circle quickly, so the depth of field is shallow.