A hard beam has a very well defined beam of illumination, with a sharp drop-off at the edge. A soft beam fades gradually out toward the edges and therefore there is a softer cutoff of light output. The field-to-beam ratio helps identify the difference between hard and soft beams. A hard beam has a low field-to-beam ratio because its field angle is very close to the beam angle. On the other side, a soft beam has a high field-to-beam ratio because the field angle is much larger than the beam angle.
