One of the most common stage light used today is the Fresnels luminaire. They are called a ‘Fresnel’ because they use a ‘Fresnel’ lens, recognised by the characteristic ‘stepped’ moulding on one face and the texturing on the other. Fresnels are the workhorses of stage lighting and the most common luminaire used on stage, theater, amusement parks and nightclubs.
The Fresnel lens produces a very even light that is soft at the edges and tends to project a soft shadow. Because the edge of the light is soft, it is not absolutely precise and will blend easily with the edges of other Fresnels to give smooth stage coverage. Theatrical Fresnels are typically made in 8, 6 or 3 inch varieties, referring to the diameter of the lens, with lamps ranging in power from 150 W (typically with a 3-inch fresnel) to 2000 W (with an 8-inch fresnel).